Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only Copyright 1976.All rights reserved TRANSFER RNA: MOLECULAR STRUCTURE, SEQUENCE, AND PROPERTIES 0934 Alexander Rich and U L RajBhandary Department of Biology, Massachusetts Institute Cambridge, Massachusetts 02139 of Technology, CONTENTS INTRODUCTION THE MULTIPLE BIOLOGICAL FUNCTIONS OFtRNA tRNA in Protein Cycle Synthesis tRNA the Regulation Enzyme and of Synthesis Aminoacyl-tRNA Transferases tRNA Participation Polynucleotide in Synthesis tRNA anEnzyme as Inhibitor tRNA Changes in Cells NEWER METHODS PURIFICATIONAND SEQUENCE FOR ANALYSISOF tRNA Purification of tRNAs Sequence Analysis tRNA of GENERAL OF FEATURES SEQUENCES tRNA Generalized Secondary Structure tRNAs for Invariant Semi-invariant and Nucleotides tRNAs in Unique Features Initiator tRNA in Sequences MOLECULAR STRUCTURE NUCLEIC ACID COMPONENTS OF AND DOUBLE HELICAL ACIDS NUCLEIC CRYSTALLIZATION OF tRNA High Resolution Crystals Yeast TM of tRNel Solution of X-ray Diffraction Patterns Using Heavy-Atom Derivatives TM SOLUTION THEYEAST OF tRNA STRUCTURE X-RAYDIFFRACTION BY Folding the Polynucleotid, Chainat 4-.~ Resolution 1973 of e Tertiary Interactions 3-AResolution 1974, at Tertiary Interactions andCoordinates 2.5-A Resolutions 1975 at THREE-DIMENSIONAL OFYEAST ~ STRUCTURE tRNA Aeceptor Stem T~C and Stem Loop D and Stem Loop Anticodon and Stem Loop 806 807 807 807 808 808 808 809 809 810 812 813 815 817 818 819 821 823 823 825 825 827 828 829 829 830 835 837 805 Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only 806 RICH & RAJBHANDARY GENERAL STRUCTURE tRNA OFOTHER MOLECULES General Observations Regarding Structure tRNA Future onYeast eh~ Work tRNA SOLUTION tRNA STUDIES OF Chemical Modification On Studies Yeast p~e tRNA Chemical Modification Studies theOther on tRNAs Useof NMR Spectroscopy the Analysisof tRNA for Structurein Solution SusceptibilitytRNA of towards Nucleases Oligonucleotide Experiments Binding tRNA CONFORMATIONAL AND CHANGES BIOLOGICAL FUNCTION BIOLOGICAL OF MYSTERIES RNA TRANSFER 838 840 841 841 842 843 845 847 848 " 850 852 INTRODUCTION Research in the field of transfer RNA (tRNA)has undergone revolutionary changes in the past few years Although there has been a steady accumulation of chemical and biological information concerning this moleculefor almost 20 years, until 1973 there was no firm information available about the three-dimensional structure of the ehe molecule Ear.ly in 1973, however, the polynucleotide chain of yeast tRNA was traced in a 4-A X-ray diffraction analysis (1) Structural workhas progressed rapidly since then to the point where atomic coordinates are now available as derived from 2.5-.~ X-ray diffraction analyses from two different crystal forms of the same molecule (2-4) Knowledge the detailed three-dimensional structure of the molecule of makesa distinct change in the type of research that can be carried out Weare now in a position to ask manydetailed questions concerning both the chemistry and the biological function of tRNA,using the structural information to guide our thinking The aim of this review is to describe in somedetail the manr~erin whichwe have obtained knowledgeof the three-dimensional structure of one tRNAspecies and to discuss the extent to which it explains and makesunderstandable various aspects of the chemistry and solution behavior of this and other tRNA species Wereview tRNA sequences and the methods of obtaining them Wealso try to direct attention toward unsolved problems associated with tRNAchemistry and point out various types of research that are beginning to lead us toward a more detailed molecular interpretation of tRNAbiological function The major biological function of tRNA related to its role in protein synthesis is The existence of a molecule-like tRNA in a sense madenecessary by the fact that is although Nature encodes genetic information in the sequence of nucleotides in the nucleic acids, it generally expresses this biological information in the ordered sequence of amino acids in polypeptide structures Transfer RNA a fundamental has biological role in acting at the interface betweenpolynucleotides and polypeptides It works in the ribosome by interacting with messenger RNA one end while at at the other end it contains the growing polypeptide chain Wedo not knowhowthis process occurs, but a detailed knowledgeof the three-dimensional structure of one species of tRNAmeansthat we are now in a position to ask intelligent questions about the molecular dynamicsof this biological function, Transfer RNA involved in a large numberof biological processes and it would is be impossible to review adequately within the confines of any one article all of the Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only STRUCTURE OF TRANSFER RNA 807 research going on in this field Wewill of necessity be selective in this review Fortunately, a number of excellent reviews dealing with various aspects of tRNA have been published recently The review by Sigler (5) covers manyof the aspects of structure determination A comprehensive review of chemistry (6) is available and chemical modifications of tRNAare reviewed by Zachau (7) and Cramer & Gauss (8) Other reviews concern the role of tRNA protein synthesis (9-11), biosynthein sis of tRNAincluding the role of tRNAmodifying enzymes, tRNAmaturation cnzymcsand tRNA nucleotidyl transferase in this process (12-15), and the structure and function of modified nucleotides in tRNA(16) THE MULTIPLE BIOLOGICAL FUNCTIONS OF tRNA Althoughthe role of tRNA protein synthesis is usually emphasized, it is imporin tant to recognize that this moleculeis involved in many other biological functions They are outlined here; several of these specialized functions have been the subject of other recent review articles tRNA Cycle in Protein Synthesis During protein synthesis tRNA interacts with a large numberof different proteins that play an important role in its biological function All tRNA molecules end in a common sequence, CCA,which is added by the nucleotidyl transferase enzyme to the 3’-end of the molecule Animportant step in protein synthesis is the specific aminoacylation, which is carried out by meansof 20 different tRNA-aminoacylating enzymes or aminoacyl tRNAsynthetases These enzymesrecognize only a specific set of isoacceptor tRNA’sas substrates and require ATPfor the initial activation of the amino acid before it is transferred onto the tRNA.Although the amino acid is added to the 3’-terminal adenosine, it has been found recently that someof these enzymesaminoacylate on the 2’ hydroxyl and some on the 3’ hydroxyl groups (17, 18) There have been two recent reviews discussing the various aminoacyl-tRNA synthetascs (19, 20) The aminoacyl tRNA(aa-tRNA) is carried into the ribosome complexed with the transfer factor EF-Tu(21) in prokaryotes or EFI in eukaryotes It should be noted et that the initiator tRNA~ has its ownfactor for ribosomal insertion Inside the ribosome tRNA interacts with a numberof ribosomal proteins including the peptidyl transferase before it is finally released from the ribosome after its aminoacid has been transferred to the growingpolypeptide chain of an adjacent tRNA.Ribosomal processes have been reviewed in a recent volu~ne (22) Although a fair amount is knownabout various aspects of tRNA biosynthesis and function during protein synthesis, virtually nothing is knownabout the manner in which tRNAmolecules are degraded tRNA and the Regulation of Enzyme Synthesis Oneof the remarkable features ofaa-tRNA the fact that it has been shownto play is a role in regulating the transcription of messengerRNA enzymesassociated with for biosynthesis of its aminoacid This was first discovered in the operon for histidine biosynthesis The regulatory role of tRNAhas been reviewed recently (23, 24) Annual Reviews www.annualreviews.org/aronline 808 RICH & RAJBHANDARY Although most of the regulatory studies have been carried out on prokaryotic systems, it has recently been demonstrated that aa-tRNA in mammaliansystems also regulates amino acid biosynthesis (25) Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only Aminoacyl-tRNA Transferases Aminoacyl-tRNA transferases are a group of enzymes that catalyze the transfer of an amino acid from aa-tRNAto specific acceptor molecules without the participation of ribosomes or other kinds of nucleic acid The acceptor molecules can be divided into three classes: (a) The acceptor can be an intact protein, in whichcase the amino acid is added to the N-terminus of the protein (26) (b) The acceptor be a phosphatidyl glycerol molecule (27), in which case the enzymecatalyzes the formation of aminoacyl esters of phosphatidyl glycerol that are componentsof cell membranes.(c) The acceptor is an N-acetyl muramylpeptide, an intermediate the synthesis of interpeptide bridges in bacterial cell walls (28) Theseare important links in cell wall biosynthesis, and somewhatspecialized tRNAs are used for this (29) The aa-tRNAtransferases have recently been reviewed by Softer (30) tRNA Participation in Polynucleotide Synthesis Reverse transcriptase is an enzymefound in oncogenic )’iruses that is used for making a DNA copy of the viral RNA.It has been found that a particular species of tRNAis used as a primer in this process (31) Avian myeloblastosis reverse Trp, whereas the murine leukemia virus enzyme uses transcriptase uses tRNA Pr° as a primer Recent studies have further shownthat the reverse transcriptRNA tase has a strong affinity for the tRNA primer (31a) Aninteresting finding that may bear somerelationship to the above is the fact that manyplant viral RNAs possess a "tRNA-like" structure at the 3’-end of the RNA.A number of plant viral RNAs (32) as well as an animal viral RNA (33) found to act as substrates for aminoacylation by aa,tRNAsynthetases The work of Haenni and coworkers (33a) suggests that bacterial viral RNAs also possess may somefeatures of"tRNA-like" structures, although not at the 3’-end Furthermore, one of the proteins that binds specifically to aa-tRNA,the transfer factor EF-Tu (21), is also a component the enzyme replicase (34), which is involved in of Q/3 replication of the bacterial viral RNA Whetherthese "tRNA-like" structures that appear to be present in manyplant and bacterial viral RNAs play a role in the specific recognition of these RNAsby the corresponding RNA rcplicases is an interesting possibility that needs to be explored further tRNA as an Enzyme Inhibitor tRNA a potent inhibitor of E coli endonuclease I The work of Goebel& Helinski is (35a) suggests that tRNA alters the modeof action of endonuclease I from that double strand scission of DNA a nicking activity to Tyr A specific isoacceptor species of tRNA in Drosophila has been found to act as an inhibitor to the enzymetryptophan pyrrolase (35b), which is involved in the conversion of tryptophan to an intermediate in brown-pigmentsynthesis In this case, an unchargedtRNA appears to act in a regulatory capacity by directly interfer- Annual Reviews www.annualreviews.org/aronline STRUCTURE OF TRANSFER RNA 809 ing with an individual enzymatic activity, although alternative explanations have been proposed recently (35c) Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only tRN/I Changes in Cells There is a large literature dealing with changesthat have been observed in the cell content of tRNAs Tworeview articles (23, 36) summarize a variety of results dealing with the changes of tRNA that occur in embryogenesisduring various stages of development It is not clear whether these changes reflect an expression of the role of tRNAin regulatory systems such as those discussed above or whether they are involved in the regulation or modificationof other functions as well In addition, there is a substantial literature reviewed in Cancer Research dealing with changes in tRNA during oncogenesis; an entire volumeis devoted to this subject (37) The relationship of these changes to the changes observed during development is a subject that needs to be explored more fully in the future Why tRNA is used in such a large variety of biological functions? It is true that this class of molecules has been involved in the biochemistry of living organisms from the very onset of the evolutionary process and it may /’effect the fact that Nature is opportunistic in using such molecules for other purposes; however, it is important to point out that we not understand the rationale behind the multiplicity of functions carried out by tRNAmolecules In a large numberof biological functions, tRNA interacts with protein molecules in a highly specific manner.The nature of these interactions is largely unknown, but it is probable that the interactions involve the recognition of tRNA distinct from as other species of RNA the three-dimensional folding of the molecule and the by detectio n of specific nucleotides or nucleotide sequences in tRNA manyproteins by With our understanding of the three-dimensional conformation of one species of tRNA,we can now ask about the extent to which this molecular structure may serve as a useful guide for understanding the detailed manner in which tRNA interacts with a variety of proteins while carrying out a large numberof different biological functions NEWER METHODS FOR ANALYSIS OF tRNA THE PURIFICATION AND SEQUENCE The first tRNAmolecule was sequenced in 1965 (38); the sequence of about different tRNAsis now known This wealth of sequence information has been invaluable both in understanding certain aspects of structure-function relationships (7, 39) and in establishing the generality of secondary structure of tRNAs.Now that the three-dimensional structure of a tRNAhas been elucidated, the major aim in tRNA sequence studies in the future will be geared more toward understanding the role of tRNAs regulation and control processes and in specific aspects of protein in biosynthesis, rather than for the sole purpose of compiling tRNA sequences These could include, for instance, sequence studies of eukaryotic suppressor tRNAs (40), tRNAsfrom eukaryotic organelles such as mitochondria and chloroplasts, tRNAs found specifically in tumor cells, tRNAs knownto undergo changes during develop- Annual Reviews www.annualreviews.org/aronline 810 RICH & RAJBHANDARY ment, and other tRNAs potentially involved in the regulation of protein synthesis and activity (23) Most of these tRNAs expected to be available only in limited are amounts Consequently, the development of methods that allow the rapid purification and sequence analysis of tRNAs a very small scale will play an important on role in future work on tRNAs Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only Purification of tRNAs Followingthe earlier use of countercurrent distribution (42) in tRNA purifications, two of the most widely used methods in recent years have been chromatography on BD-cellulose (43) and on DEAE-Sephadex (44) These and other procedures suitable for large-scale purification have been described elsewhere (45) Kelmers and co-workers have recently developed two new high-pressure "reversed phase chromatography" systems, RPC-5 and RPC-6 (46) Of these two, RPC-5has been the one most widely used The principle behind the separation involves both ion exchange and hydrophobic interactions between the tRNAsand the coating material (47, 48) On the analytical scale (49), the RPC-5system been particularly useful for monitoring changes in tRNA isoacceptor patterns during development (50) and differences between normal and tumor-cell tRNAs(51, 52) and between tRNAsfrom quiescent cells and those from proliferative cells (53) Several reports have described large-scale purification of mammalian (54), Escherichia coli (55), and Drosophila (47, 56) tRNAsusing RPC-5 chromatography Although initially described as a method for tRNApurification, RPC-5 has proved equally useful for the rapid separation of mononucleotides,oligonucleotides present in total T~- or pancreatic RNasedigests oftRNA (55, 57, 58), large oligonucleotide fragments present in partial digests of tRNAs (55), homopolynucleotides (59), and even ribosomal RNAs(60) Using analogies of RPC-5 with anionexchange polystyrene resins, Singhal (61) has developed Aminex-A28 an alternaas tive chromatographic support for tRNAseparations It is reported (62) that the resolution obtained on Aminex-A28is superior to that on RPC-5, and B Roe (personal communication) has used Aminex-A28 the purification of tRNAsfrom in mammalian sources Chromatography on Sepharose 4B has been used recently for the large-scale purification of E coli tRNAs(63) The tRNAsare adsorbed to the Sepharose the presence of a high concentration of ammonium sulphate at slightly acidic pH; elution of the tRNAsis then carried out with a linear negative gradient of amu moniumsulphate Holmes et al (63) have purified E coli tRNA~ in a simple two-step column chromatography using Sepharose 4B as the first step and RPC-5 as the second Other workers have described the use of anion-exchange Sepharose 6B (64) and of various aminoalkyl derivatives of Sepharose 4B (65) in separation of tRNAs Another methodapplicable to the purification of specific tRNAs takes advantage of the fact that two tRNAswhose anticodon sequences are complementary form a 1:1 tRNA: tRNAcomplex The association constant of complex formation between Phe Glu yeast tRNA (anticodon sequence GmAA) and E coli tRNA (anticodon se- Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only STRUCTURE OF TRANSFER RNA 811 -~ quence s2UUC) of the order of 107 mole (66, 67) Grosjean et al (68) is ehe by covalent linkage through its 3’-end to polyacrylaimmobilized yeast tRNA mide (Biogel P20) Uponchromatography of crude E colt" tRNAthrough such a 6~u 6~u column, tRNA is specifically retarded and a 19-fold enrichment of tRNA is obtained after a single passage Similarly, E coli tRNAprecursors have been purified by chromatography of a mixture of [32p]tRNA precursors on columns containing the appropriate tRNAsimmobilized onto them (69) In another technique, the specificity of antigen-antibodyinteractions is exploited Phe for the detection and purification of tRNA species that contain the fluorescent nucleoside Y or its derivatives by immobilizing antibodies against Y nucleoside on columns (70, 71) Several of the newer methods for tRNApurification involve aminoacylation of the desired tRNA with a specific aminoacid as the first step in their purification The most widely used procedure is that ofTener and co-workers (72), which in most cases includes the further derivatization of the amino group of aa-tRNAwith an aromatic moiety The chemically derivatized aa-tRNAis then selectively retarded on a column of BD-cellulose and thus separated from uncharged tRNA In an example of this approach, aa-tRNAcarrying a p-chloromercury phenyl group is separated from uncharged tRNAby chromatography on a column of Sepharose 4B containing reactive thiol groups (73) By this method,leucine, arginine, and tyrosine tRNAsfrom E coli have been obtained in a high state of purity The ability of aa-tRNAsto form a ternary complex with the E coli protein synthesis elongation factor EF-Tuin the presence of GTPhas been used by Klyde & Bernfeld (74) in the purification of chicken liver aa-tRNAs.The ternary complex is separated from any free aa-tRNAor uncharged tRNAby gel filtration on Sephadex G-100(75) In the presence of limiting amounts of aa-tRNA,virtually all of the aa-tRNA forms the ternary complex The procedure appears general and Phe has led to the i~olation of 90%pure tRNA and highly purified preparations of set, TM tRNA tRNAL%and tRNA A major difference between aa-tRNAs and uncharged tRNAis that the latter contains a free 2’,3’-diol end group at its 3’-terminal adenosine, whereas the former does not This difference has been exploited by McKutchan al (76) in a general et procedure for the fractionation of aa-tRNAsfrom uncharged tRNAsusing a column of DBAE-cellulose, which contains dihydroxyl boryl groups attached to aminoethyl cellulose Uncharged tRNAscontaining cis-diol groups form specific complexes with the dihydroxyl boryl groups and are retained on the column, whereas aa-tRNA is not retarded on the column (77-79) Several groups (80-83) have described the use of two-dimensional gel electrophoresis on polyacrylamide the simultaneouspurification of different 32p-labeled for small RNAs a single step Fradin et al (82) have used two-dimensional gel in electrophoresis for the separation of yeast tRNAand yeast tRNAprecursors Several of the yeast tRNAswere shownto be homogeneous fingerprint analyses by (82) This technique has also been used more recently for the purification 3~P-labeled tRNAsisolated from HeLacell mitochondria (J D Smith, personal communication) Annual Reviews www.annualreviews.org/aronline 812 RICH & RAJBHANDARY Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only Sequence Analysis of tRNA The basic principles involved in the sequence analysis oftRNAs have been published by Brownlee(100) Techniques developed by Sanger and co-workers (84, 85) suitable for work on 3~p-labeled tRNAs have greatly simplified both the separation and sequence analysis of tRNAs, and these account to a large extent for the dramatic increase in the knowledge of tRNAsequences, particularly from prokaryotic sources such as E coil and Salmonella In spite of these remarkable advances, sequence analysis of most eukaryotic tRNAs(notably from yeast, wheat germ, and mammalian sources) has still used the more classical procedure involving the identification of nucleotides by their ultraviolet absorption spectra, due to the problems involved in the labeling and subsequent purification of tRNAs with 32p, particularly from most higher eukaryotes The latter procedure is more time-consuming and usually requires large amounts of purified tRNAs Several methodsfor the in vitro end-group labeling of oligonucleotides or tRNAs, which make possible sequence analysis of oligonucleotides on a small scale, have now been developed (86-89) These methods have also been used for the sequence analysis of tRNAs(90-92) It can be expected that further refinements in these techniques will eventually allow sequence analysis of nonradioactive tRNAs as on little as 25-100 ~g of the tRNA 3~-END-GROUP LABELING OF OLIGONUCLEOTIDES WITH 3H A general methodfor the specific labeling of 2’,3’-diol end groups in RNAs oligonucleoand tides and its use in sequenceanalysis was described previously (93, 94) It involves first oxidation of the 2’,3’-diol end group with periodate followed by reduction of the 2’,3’-dialdehyde end group with [3H]sodium borohydride to yield a 3’-3H-labeled dialcohol derivative of the tRNA Randerath and his co-workers have now pioneered the application of this methodin the sequence analysis of oligonucleotides (89) present in T~- or pancreatic RNasedigests of an RNA have described the and sequence analysis of a yeast leucine tRNA(90) Several of the new techniques introduced by Randerath for the separation of oligonucleotides by thin layer chromatography,detection of 3Hon thin layer plates by fluorography, etc have now made this a relatively rapid and sensitive methodfor sequencing oligonucleotides (93, 95) 5’-END-GROUP LABELING OF OLIGONUCLEOTIDES WITH 32p An alternative procedure for sequence analysis of oligonucleotides on a small scale involves first the use of polynucleotide kinase for labeling oligonucleotides present in T~- or pancreatic RNase digests oftRNA with ~2p at the 5’-end (86, 96) The 5’A2P-labeled oligonucleotides are separated (84) and partially digested with snake venomphosphodiesterase These products are separated (85, 97) and the sequence of the oligonucleotide in question is deducedfrom the characteristic mobility shifts resulting ~’rom the successive removal of nucleotides from the Y-end (85, 86, 91) This approach has been used to elucidate the cytoplasmic initiator tRNAsequence of salmon testes and liver (91), human placenta (92), Neurospora cras sa (A Gillum, L Hecker, W Barnett, and U L RajBhandary, unpublished), the Annual Reviews www.annualreviews.org/aronline STRUCTURE OF TRANSFER RNA 813 ~’h" tRNA from the chloroplasts of Euglenagracilis (92a), and lysine tRNAs rabbit of liver (H Gross, M Raba, K Limburg, J Heckman, and U L Ra~Bhandary, unpublished) LABELING OF OLIGONUCLEOTIDES WITH 32p ,~zeto & $511 (88) have developed a complementary method that uses polynucleotide phosphorylase to label the 3’-ends of oligonucleotides with 32p Theseparation of the oligonucleotides and the principle behind their sequenceanalysis are similar to those for the Y-labeled oligonucleotides except that the 5’-exonuclease used for partial digestion is spleen phosphodiesterase (98) Besides providing an alternate approachto the use of polynucleotide kinase for sequencing oligonucleotides, an important application of this methodcould well be in conjunction with polynucleotide kinase for sequencing long oligonucleotide fragments (15 or longer), which are occasionally found total Tt-digests of an RNA (99) Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only 3’-END-GROUP ANALYSIS OF 5’AND 3’-END LABELED RNAs A procedure for deriving the sequence of 20-25 nucleotides from each end of a tRNA requiring and no more than a few micrograms of tRNAhas now been developed (M Silberklang, A Gillum and U L RajBhandary, in preparation) For the 5’-end, this involves labeling of the tRNA with 32p at the 5’-end with polynucleotide kinase followed by partial digestion of the 5’-labeled RNA with nuclease PI, a relatively nonspecific endonuclease from Penicillium citrinum (100a) The labeled oligonucleotides are separated by two-dimensional homochromatography and their sequence deduced as described previously (85, 86, 91) Exactly the sameprinciple is used in the sequencing of the Y-endexcept that the Y-endis first labeled with 32p using tRNA nucleotidyl transferase (15) SEQUENCE l GENERAL FEATURES OF tRNA SEQUENCES As of this writing, the sequences of about 75 different tRNAs are known(90, 91, 92, 101-114, 116, 117, 121; B Dudock, personal communication; G Dirheimer, personal communication; A Gillum, L Hecker, W Barnett and U L RajBhandary, unpublished).2 This list includes tRNA sequences for all 20 amino acids except asparagine While most of these are from yeast or E coli, someof the more recent ones sequenced have been from Bacillus stearothermophilus, Bacillus subtilis, Staphylococcus, N crassa, wheat germ, salmon, chick ceils, mammals,and human Phe t, placenta In the case of tRNA and tRNAU~ for which sequences from several ~Thenucleosides and bases are indicated by the usual symbolsC, G, A, U, T, and ¯ (pseudouridine).Themolecular structure and the numbering systemfor the four majorbases in tRNA shown Figure Modifications designatedby symbols are in are such as mTG,~, which indicates a methylgroup on position of guanineresidue 46; m~G26 indicates two methyl groupson nitrogen2 of guanine26 Methylation the 2’OH ribose is indicated by an "m" of of after the symbol such as C~2m Watson-Crick pairs are designatedby a single dot, thus base TM 2Correctedsequence yeast tRNA cited in Ref of Annual Reviews www.annualreviews.org/aronline 814 Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only Aden’ RICH & RAJBHANDARY C Uridine Figure Molecular structure and numberingsystem of the four major bases in tRNA Nucleosides illustrated with only C’~of the ribose ring in the diagram.Thegeometry are of the bases is taken froma surveyof X-raydiffraction studies (156) mammalian sources are known,these have been found to be identical It is, therefore, possible that the sequences of most if not all mammalian tRNAs have been may Tr0, conserved Similarly, the sequence of tRNA which is used as a primer for DNA synthesis by avian myeloblastosis virus reverse transcriptase, maybe identical to the corresponding tRNAfrom duck, mouse, rat, and human sources but different from E coli and from lower eukaryotes (31,122) In the case ofeukaryotic cytoplasmic initiator tRNAs,the sequences may be even more strongly conserved, since it has been shownthat these tRNAs from salmon liver and testes (91) have essentially the same sequence as that from humanplacenta (92) and from rabbit, sheep, and mouse myeloma (123, 124) Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only 848 RICH & RAJBHANDARY tial digestion used, initial cleavage of the tRNA occurred exclusively in the D loop to yield the 5’-terminal one quarter fragment pG~-Gt8and the Y-terminal three quarter fragment A21-A76 Uponprolonged incubation, the latter fragment was subsequently cleaved in the T~Cloop to yield a 37-nucleotide fragment A2~-G57 and the 3’-terminal quarter fragment mlA58-A76 Even with a large excess of enzymeand °, :+ at 37 cleavage in the presence ofMg occurred preferentially in the D loop Since GI9and G20were not present in any of the fragments, it is not known with certainty whether the initial site of attack by T~-RNase was on G~s, GIg, or G20 However, since in most tRNAsthe common residues Gts and G’t9 are relatively resistant to T~-RNase (292), and since G20is also the most readily available G residue in the D loop to chemical modifications, it is most likely that 020 was the primary cleavage phe site on yeast tRNA toward Ti-RNase No cleavage on G45 of the variable loop wasobserved, suggesting that G45is protected in the three-dimensional structure of the tRNA Essentially similar results were obtained by Samuelson & Keller (295), who phe observed quantitative cleavage of yeast tRNA in the D loop and at a muchslower rate in the Tt~C loop Under conditions when complete cleavage occurred at Gt8 and G20,no cleavage at all was found in the G~5of the same loop The above results taken together with those of Schmidt et al (294) suggest that, of the G residues e~, present in the cloverleaf structure of yeast tRNA G~s, G18, G19,G45, and G57are most probably shielded against nucleolytic attack in the tertiary structure of this tRNA Ph~ s~ An extensive survey of sites on yeast tRNA and tRNA susceptible toward several other nucleases has also been carried out by Harbers et al (244) The results with Ti-RNase and Neurospora endonuclease are basically similar to those described above With pancreatic RNase, the two most susceptible sites were the anticodon loop and the CCA-end agreement with earlier findings (290) With in T:-RNase, splitting occurred in the D loop between D~6and D17, and in the anticodon loop and the CCA-end Streeck & Zachau (297, 298) have also compared the patterns of degradation ~’~¢ and tRNA with those obtained from corres¢~ obtained from native yeast tRNA sponding denatured forms of these tRNAs Detailed studies using T~-RNase, pancreatic RNase, T2-RNase, sheep kidney nuclease, and hog spleen acid RNase revealed characteristically different partial fragmentationpatterns for the native and denatured forms These findings support the assumption implicit in these studies that the relative resistance of most of the nucleotides in the tRNAs toward partial digestion with nucleases is due to the shielding of these nucleotides in the tertiary structure of tRNAs Oligonucleotide Binding Experiments A simple and direct methodfor probing polynucleotide structures is the introduction of oligonucleotides, usually trimers or larger, to see if they will bind to the polynucleotide It became apparent from the initial studies of Uhlenbeck (310) and H/Sgenauer (300) that this would be a useful probe for tRNAstructure solution The binding is generally measuredby equilibrium dialysis, and the assump- Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only STRUCTURE OF TRANSFER RNA 849 tion is usually madethat Watson-Crick pairing will account for the observed results However, is important to realize that other effects can be important, such as the it influence of nucleotides on the base stacking of neighboring nucleotides in an oligomer, as this can influence binding constants Furthermore, other types of hydrogen bonding may occur in addition to Watson-Crick pairing Some generalizations are possible from the results of studies on several different Phe Almost all tRNAscan bind oligomers completRNAs, including yeast tRNA mentary to the last three or four bases at the 3’-end of the molecule Furthermore, they all bind oligomers complementaryto the anticodon No binding is found for the stem regions of the cloverleaf, and virtually none for the T~Cloops, even for eukaryotic initiator tRNAs with an altered nucleotide sequence in the loop (301) Somebinding, usually weaker, is found for the D loop and variabl6 loop in some cases ~’he have been carried out by manyinvestigators Experiments with yeast tRNA (302-308) Pongs and co-workers (302, 303, 308) showedthat two regions were fully accessible to binding, the 3’-terminal ACCA binding by complementary for tri- or tetra-nucleotides and the anticodon region The binding of the anticodon (UUC) was considerably augmented the addition of a fourth purine on the 3’-side, either by A or G, but less by the addition of U (308) Strong binding of larger oligomers this region has also been seen by other investigators (305, 307) Eisinger & Spahr Phe (305) reported that the pentamer UUCAG bound to yeast tRNA These results is Phe raise the question of whether or not residues 32 and 33 in the yeast tRNA sequence are available for binding in solution As pointed out above, they are unavailable in the crystal lattice However, conformationof the anticodon could the change on binding, giving rise to an altered conformation Another explanation has been offered in recent experiments comparing the binding of UUCA, UUCG, and UUC-purine (R Bald and O Pongs, unpublished data) All of these have high l’h~, even though the purine residue cannot form binding constants to yeast tRNA two hydrogenbonds to U33o It suggests that the 3’-purine, as with terminal A or G residues, acts more to stabilize the stacking of the oligonucleotide to produce a higher binding constant than to engage in hydrogen bonding In contrast to the strong binding to the 3’-end and at the anticodon, binding to ~’h~ the D and T~Cloops and the variable loop of yeast tRNA is weaker (302, 308) Using slightly different conditions, Cameron& Uhlenbeck (306) found somewhat higher binding to the D loop How we interpret binding to regions that maybe inaccessible in the crystal structure? Twoexplanations come to mind The tRNA solution maycontain somedenatured species, for it has been shownthat the pattern of oligonucleotide binding changes radically in the stable denatured form of yeast u tRNA~ (309) Alternatively, the crystal structure is a static ~,iew of what obviously a dynamic structure, and the molecule might open up, especially with competition of an oligonucleotide that can bind An explanation’ of this type has been suggested by Uhlenbeck (310) Tyr The results from other tRNAs are broadly similar E coli tRNA (310), yeast u (309), E coli (299, 300, 310, 311) and yeast tRNA~ (301), and yeast ~t tRNAL~ n¢ tRNA (312) have the anticodon as well as the 3’-end of the molecule available for Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only 850 RICH & RAJBHANDARY binding Somebinding has been reported in the D loop and variable loop of E coli Tyr u et tRNA (310), yeast tRNAL~ (309), and E coli tRNA~ (310), btit this was thought to be competingwith the native structure Little or no binding of oligomers Ile et to the D loop was found for yeast tRNA (312) or yeast tRNA~ (301) As in other tRNAs,the wobble codon (232) is also efficiently bound to the anticodon of the initiator tRNA (301) It is interesting that the codon AUG binds to both E coli et t, but tRNA~f and tRNAMn~ three times more efficiently to the former species, which maybe associated with base modifications (311) The pattern of oligonucleotide binding is changed somewhatwhen the Y base is Phe removedfrom yeast tRNA There is a decreased binding to the anticodon (303, 306), which might be expected since the Y base is adjacent and its removal would allow increased flexibility in the anticodon Somewhat less obvious is the result of a substantial change in the binding of ol~onucleotides to the D loop (306) induced by removal of the Y base some 40-50 A away Phi, In general, the three-dimensional structure of yeast tRNA which is obtained from the crystal data, is broadly compatible with the results of oligonucleotide binding studies, although further workwill be necessary to interpret someof these findings Onreviewing the results of solution studies on tRNA with the crystal structure analysis, we find striking agreementon the whole The structural model can be used to interpret a wide variety of investigations that probe many different aspects of the molecule Future work will be even more sharply focused on the question of comparing fine details of structure obtained in the crystallographic studies with those derived from solution studies Indeed, the availability of the three-dimensional structure should makepossible even more rigorous tests in the future The molecule is dynamic, even though the crystallographic structure results are static In the future, solution studies should provide important access to the detailed nature of the tRNA molecular movements tRNA CONFORMATIONAL CHANGES AND BIOLOGICAL FUNCTION Phe With the structure of yeast tRNA knownin one conformation, a crucial question is whether the molecule changes its conformation during biological function While the evidence at present is not conclusive, it suggests strongly that changesdo occur The type of conformation changes that the molecule can undergo has certain constraints The photo-cross-linking experiments tying s4U8 with C13 (207) yield molecule capable of aminoacylation and protein synthesis, whichsuggests that this part of the molecule is not likely to unfold during these processes Furthermore, it is possible to attach an affinity label onto the sulfur atom of s4U8in E coli ~’he, and the molecule functions normally (313) This label fills the groove tRNA between the D stem and the Tt~C stem, so that space must not be intruded into during aminoacylation or ribosomal passage Does the tRNA molecule change conformation after interaction with the aminoaPhe cyl synthetases? An NMR study of yeast tRNA (314) showed no change upon aminoacylation However,these experiments are ditficult because of the lability of Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only STRUCTURE OF TRANSFER RNA 851 the aminoacyl ester bond at the 3’-terminal ribose Experiments by Kanet al (315) have utilized tRNAthat has an NH2 group in place of the 3’-OHand forms a stable amide linkage between the amino acid and the tRNA (316) An NMR study Phe showed two peaks in the low-field spectrum amide-linked phenylalanyl-tRNA that were altered (315) It is not clear which hydrogen-bondedinteractions are involved, but these results suggest a small change in conformationupon aminoacylation Further work will be needed to resolve this question What happens when the tRNA goes into the ribosome? The experiments of Erdmannand his colleagues (241, 242, 319) strongly suggest that the Tt~C loop disengages from the D loop and opens up so that the sequence T~Cis nowavailable for binding, possibly to a complementarysequence GAA the ribosomal 5S RNA on They have shown that the tetranucleotide T~CG will prevent the binding of aa-tRNAto the A site on the ribosome Furthermore, T~CG would not prevent the binding of initiator tRNA the P site (320), reinforcing the idea that the function to of this loop in initiator tRNAis somewhatdifferent from that found in chainelongating tRNAs These experiments have been extended by Gassen and co-workers (317, 318), who have shown that CGAA bound, presumably to the Tt~C(3 is Phe, only when the tRNAcombines with the eodon These experiments were tRNA carried out either with ribosomal subunits and an oligouridylate (U7_8) mRNA fragment or with U7_8alone The suggestion is that the tRNA molecule is capable of undergoing a conformational change in the region of the oTt~C loop when an interaction occurs at the anticodon loop approximately 60-70 A away These results bring to mind the oligonucleotide binding experiments showing that removal of the ahc Y base from the anticodon loop of yeast tRNA led to altered binding of an oligonucleotide complementary to the D loop (306) These both suggest that modification in the antlcodon loop can bring about a change in the molecule that o can be detected about 50 A away A similar phenomenon been reported by Wells has and his colleagues (115, 119), whohave measuredthe stabilization of one region a DNA helix by an adjacent region that may be 15 base pairs (~50 ,~) removed This phenomenon was termed telestability What is observed in the tRNAmolecule may be a more complex version of the same phenomenon This may be an expression of the fact that the tRNA molecule exhibits long-range order, and therefore modifications in one part of the molecule maybe expressed by changes in properties at another part of the molecule As mentioned above, the tRNA molecule is a dynamicsystem, and these effects maybe an expression of this property A long-distance interaction, such as the one described linking conformational changes in the anticodon with changes in the D loop, may help to explain the x~ otherwise puzzling observations concerning E coli tRNA Mutation of the G24 of the D stem to A24 enables this tRNA alter its anticodon function so that it to acts to suppress termination without changing the anticodon sequence (138) This might suggest that a conformational change is induced in the anticodon as a consequence of an alteration in the D stem It is quite clear that tRNA be made to undergo conformational changes as, can for example,in thermal denaturation, whichhas been studied in a variety of investigations (120, 140, 145, 309) A detailed and comprehensivestudy of the unfolding Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only 852 RICH & RAJBHANDARY et of tRNA~ has been carried out by Crothers et al (145) A conformational change has also been observed at roomtemperature by measuring the diffusion constant of 2+ tRNAas a function of ionic strength (1491) In I mM and at ionic ~tr ength 0.I, the diffusion constant of both unfractionated E coli tRNAand pure yeast ~’he tRNA was found to rise sharply, indicating that the molecule had folded into a more compact form Raising or lowering the ionic strength resulted in a decreased diffusion constant This has been interpreted as an environment in which the Tq~C and D stems disengage, and the two limbs of the L-shaped molecule fold together Thestability oftRNA conformationis thus a sensitive function of the salt concentration, and it remains to be seen whether this is related to functional changes Manyof the future studies of tRNAconformation will undoubtedly be directed toward the goal of understanding what happens when it carries out its biological functions Movement tRNA of clearly occurs inside the ribosome, and the relation between the tRNAand the ribosomal A site and P site is yet to be understood A suggestion has been made that movement between these two sites may have a rotatory component, perhaps associated with a turning of the mRNA when it is being read (296) In another model, there is no movement the tRNAbetween of and P sites (299) However,we not have enoughdata at present to evaluate ideas of this type The next phase of work on tRNAis likely to involve a more direct structural approachto the biological function of the molecule In this work, it is likely that knowledgeof the three-dimensional structure will play an essential role BIOLOGICAL MYSTERIES OF TRANSFER RNA There are many unknownfeatures associated with the tRNAmolecule Knowing the three-dimensional structure in a sense helps us gain perspective in that we can sometimes separate things that we understand from things we not understand r’he The three-dimensional structure of yeast tRNA yields structural reasons for most of the invariant and semi-invariant bases in this tRNA species and, by inference, in most other tRNAspecies as well In a sense this provides us with a very good frameworkfor understanding a large part of the information imbeddedin the tRNA sequences Most of the functional aspects of tRNA are not knownat present, but we have some understanding about how to proceed in our research to learn more about them From the comparative information embodied in the tRNAsequence data, however, we learn of three major my~teries~base modification, variations in the a- and B-regions of the D loop, and the tRNAs with large variable loops Whatis the biological role of the base modifications, whichare varied and great in number?Are they associated with the role of tRNAin protein synthesis? It is likely that some of them are; for example, N2 methylation of a non-cognate tRNA substrate for yeast phenylalanine synthetase at position G~oresults in faster ami~’h~ substrate has a noacylation by the enzyme(59) Since the normal yeast tRNA methyl group in that position, it is reasonable to believe that this modification may be involved in specificity of aminoacylation Another example, but not involving protein synthesis, is found in the repressor activity of Salmonella ni~ histidyl-tRNA Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only STRUCTURE OF TRANSFER RNA 853 In a mutant tRNAwhere the conversion of a U to ~ in the anticodon stem of his tRNA is blocked, there is no repression of the transcription of the histidine operon (23, 49) In this case, the base modification is necessary for the tRNA regulatory activity However, these examples very rare, since the biological role of the large are bulk of modified bases in tRNAis unknown A second mystery concerns the D loop and the large number of variations in tRNA sequence in the ct- and fl-regions They can have one to three nucleotides; most of them are pyrimidines and 70%of the nucleotides are dihydrouracil (125) In the three-dimensional structure, the bases of the a- and B-regions are near each other on th.e surface of the moleculewhere they can interact with other molecules It has been suggested that they could be a recognition region for synthetases (137), but that is unlikely since someisoacceptor tRNA species have different numbersof nucleotides in the ct- and fl-regions, even though they are all recognized by the same enzyme The biological function of the variations in the ct- and ,8-region is not obvious The third mystery surrounds the large variable loops (13-21 nucleotides), which account for approximately 20%of the knowntRNAsequences They are confined to three species in prokaryotes serine, leucine, and tyrosine but eukaryotic tyrosine tRNA does not have a large variable loop Is this phenomenon related to the role of tRNA protein synthesis or are other functions involved? in At present, we not have answers to these questions, but stating the questions sometimesfacilitates and directs our research activities toward their solution ACKNOWLEDGMENTS This work was supported in part by grants from the National Institutes of Health, the National Science Foundation, the American Cancer Society, and the National Aeronautics and Space Administration Literature Cited Kim,S H., Quigley, G J., Suddath, F L., McPherson, Sneden,D., Kim, A., J J., Weinzierl, J., Rich, A 1973 Science 179:285-88 Quigley, 13 J., Seeman,N C., Wang, A H., Suddath,F L., Rich, A 1975 Nucleic Acids Res 2:2329-41 Sussman, L., Kim,S H 1976 BioJ chem, Biophys Res Commun.68: 89-96 Ladner,J E., Jack, A., Robertus, D., J Brown, S., Rhodes, Clark, B F R D., C., Klug, A 1975 Nucleic Acids Res 2:1929-37 Sigler, P B 1975.Ann.Rev Biophys Bioeng 4:477-527 Brown,D M.1974 Basic Principles in Nucleic Acid Chemistry, ed P.O.P T’so, vol 2, Chap London:Academic Zachau, H 1972 The Mechanismof ProteinSynthesis its Regulation, and ed L Bosch, pp 173-217 Amsterdam: North Holland Cramer, Gauss,D H 1972.SeeRef F., 7, pp 219 41 Ochoa, S., Mazumder,R 1974 The Enzymes10:1-51 10 Lucas-Lenard, Laszlo, B 1974 The J., Enzymes 10:53-86 11 Tate, W.P., Caskey,C T 1974 The Enzymes 10:87-118 12 Schaefer, K., $611, D 1974 Biochimie 56:795-804 13 Altman,S 1975 Cell 4:21-9 14 Smith, J D 1976 Prog Nucleic Acid Res Mol BioL 16:25-73 15 Deutscher, M P 1973 Prog Nucleic Acid Res Mol.Biol 13:51-92 Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only 854 RICH & RAJBHANDARY 16 Nishimora, S 1972 Prog Nucleic Acid Res Mol Biol 12:49-85 17 Sprinzl, M., Cramer, F 1975 Proc Natl ,4cad Sci USA72:3049-53 18 Fraser, T H., Rich, A 1975 Proc Natl ,4cad Sci US,4 72:3044-48 19 Kiselev, L L., Favorova, O O 1974 ,4dr Enzymol 40:141-221 20 S/511, D., Schimmel,P R 1974 TheEnzymes 10:489-538 21 Lucas-Lenard, J., Lipmann, F 1971 Ann Rev Biochem 40:409-48 22 Nomura,M., Tissieres, A., Lengyel, P., eds 1974 Ribosomes NewYork: Cold Spring Harbor Lab 930 pp 23 Littauer, U Z., Inouye, H 1973 Ann Rev Biochem 47:439-70 24 Brenchley, J E., Williams, L S 1975 ,4nn Rev Microbiol 29:251 74 25 Simpson,D R., Arfin, S M., Hatfield, G W 1975 Fed Proc 34:586 26 Softer, R L 1973 Mol Cell Biochem 2:3-14 27 Gould, R M., Lcnnarz, W J 1970 J Bacteriol 104:1135~4 28 Strominger, J L 1970 Harvey Lect 64:179-213 29 Roberts, R J 1972 Nature NewBiol 237:44-46 30 Softer, R L 1974 ,4dr Enzymol 40:91-140 31 Sawyer, R C., Harada, F., Dahlberg, J E 1974 J Virology 13:1302-11 31a Panet, A., Hazeltine, W A., Baltimore, D., Peters, G., Harada, F., Dahlberg, J E 1975 Proc Nat Acad Sci U.S.,4 72:2535-39 32 Yot, P., Pinck, M., Haenni, A-L., Duranton, H M., Capeville, F 1970 Proc Nat ,4cad Sci USA67:1345-49 33 Salomon, R., Littauer, U.Z 1974 Nature 249:32-33 33a Prochiantz, A., Benicourt, C., Carre, D Haenni, A-L 1975 Eur J Biochem 52:17-23 34 Blumenthal, T., Landers, T A., Weber, K 1972 Proc Nat ,4cad Sci US,4 69:1313-17 35a Goebel, W., Helinski, D R 1970 Biochemistry 9:4793-4801 35b Jacobson, K B 1971 Nature New Biol 231:17-19 35c Mischke, D., Kloetzel, P., Schwochan, M 1975 Nature 255:79-80 36 Sueoka, N., Kano-Sueoka, T 1970 Prog Nucleic Acid Res Mol Biol 10:23-55 37 Cancer Res 1973 Vol 33 38 Holley, R W., Apgar, J., Everett, G A., Madison, J T., Marquisee, M., Merrill, S H., Penswick, J R., Zamir, A 1965 Science 147:1462-65 39 Ofengand,J 1976 In Protein Synthesis, ed H Weissbaeh, S Pestka Inpress 40 Gesteland, R F., Wolfner, M., Grisafi, P., Fink, G., Botstein, D., Rother, J R 1976 Cell 3:381-90 41 RajBhandary, U L., Chang, S H 1968 J Biol Chem 243:598-608 42 Doctor, B P., Apgar, J., Holley, R W 1961 J Biol Chem 236:1117-20 43 Gillam, I., Millward, S., Blew, D., von Tigerstrom, M., Wimmer,E., Tener, G M 1967 Biochemistry 6:3043-56 44 Nishimura, S., Harada, F., Narushima, U Seno, T 1967 Biochim Biophys Acta 142:133-38 45 Cantoni, G L., Davies, D R., eds 1971 Procedures in Nucleic "4cid Research, Vol NewYork: Harper & Row 46 Pearson, R L., Weiss, J F., Kelmers, A D 1971 Biochim Biophys Acta 228:770-74 47 White, B M., Dunn, R., Gillam, I., Tener, G M., Armstrong, D J., Skoog, F., Biol Chem.R., Leonard, N J 1975 J Frihart, C 250:515-25 48 Kelmers, A D., Heatherly, D E 1971 ,4hal Biochem 44:486-95 49 Singer, C E., Smith, G R., Cortese, R., Ames, B N 1972 Nature New Biol 238:72-74 50 White, B N., Tener, G M., Holden, J., Suzuki, D T 1973 J Mol Biol 74:635-51 51 Grunberger, D., Weinstein, I B., Mushinski, J F 1975 Nature 253:66-67 52 Katze, J R 1975 Biochim Biophys Acta 383:131-39 53 Juarez, H., Juarez, D., Hedgcoth, C., Ortwerth, B J 1975 Nature 254: 359-60 54 Pearson, R L Hancher, C W., Weiss, J F., Holliday, D W., Kelmers, A D 1973 Biochim Biophys Acta 295: 236-49 55 Roe, B., Marcu, K Dudock, B 1973 Biochim Biophys ,4cta 319:25-36 56 White, B N 1975 Biochim Biophys ,4cta 395:322-28 57 Egan, B Z 1973 Biochim Biophys Acta 299:245-52 58 Singhal, R P 1973 Biochim Biophys ,4cta 319:11-24 59 Roe, B., Sirover, M., Dudock, B 1974 Biochemistry 12:4146-54 60 Kelmers, A D., Heatherly, D E., Egan, B Z 1974 Methods Enzymol 29:483-86 Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only STRUCTURE OF TRANSFER RNA 61 Singhal, R P 1974 Sep Purif Methods 3:339-98 62 Singhal, R P 1974 Eur J Biochem 43:245-52 63 Holmes, W M., Hurd, R E., Reid, B R Rimerman,R A., Hatfield, G W 1975 Pro¢ Natl Acad Sci USA 72:1068-71 64 Leberman, R., Glovanelli, R., Acosta, Z 1974 Nucleic Acids Res 1:1007-16 65 Dziegielewski, T., Jakubowski,H 1975 J Chromatogr 103:364-67 66 Eisinger, J 1971 Biochem Biophys Res Commun.43:864-61 67 Eisinger, J., Gross, N 1975 Biochemistry 14:4031-41 68 Grosjean, H., Takada, C., Petre, J 1973 Biochem Biophys Res Commun 53:882-93 69 VSgeli, G., Grosjean, H., S~511,D 1975 Proc Natl ,4cad Sci USA72:4790-94 70 Salomon, R., Fuchs, S., Aharonov, A., Giveon, D., Littaucr, U Z 1975 Biochemistry 14:4046-50 71 RajBhandary, U L., Faulkner, R D., Stuart, A 1968 J Biol Chem 243: 575-83 72 Gillam, I D., Blew, D., Warrington, R C., von Tigerstrom, M., Tenet, G M 1968 Biochemistry 7:3459-68 73 Goss, D J., Parkhurst, L J 1974 Biochem Biophys Res Commun 59: 181-87 74 Klyde, B J., Bernfeld, M R 1973 Biochemistry 12:3752-57 75 Ono, Y., Skoultchi, A., Klein, A., Lengyel, P 1969 Nature 220:1304-7 76 McKutchan, F., Gilham, P T., SiSll, T D 1975 Nucleic Acids Res 2:853-64 77 Duncan, R E., Gilham, P T 1975 Anal Biochem 66:532-9 78 Khym, X 1967 Methods Enzymol 12:93-101 79 Rosenberg, M 1974 Nucleic Acids Res 1:653-71 80 Ikemura, T., Dahlberg, J E 1973 J Biol Chem 248:5024-32 81 Ikcmura, T., Shimura, Y., Sakano, H., Ozeki, H 1975 J Mol Biol 96:69-86 82 Fradin, A., Gruhl, H., Feldman, H 1975 FEBSLett 50:185-9 83 Stein, M., Varricchio, S 1974 Anal Biochem 61:112-19 84 Sanger, F., Brownlee, G G., Barrell, B G 1965 J Mol Biol 13:373-89 85 Barr¢ll, B G 1971 See Ref 45, pp 751-59 86 Simsek, M., Ziegenmeyer, J., Heckman, J., RajBhandary L 1973 Proc Natl U Acad Sci USA 70:1041-45 855 87 Szekely, M., Sanger, F 1969 J Mol Biol 43:607-17 88 Szeto, K S., S~511, D 1974 Nucleic Acids Res 1:171-81 89 Randerath, K., Randerath, E 1971 Methods Cancer Res 9:3-69 90 Randerath, K., Chia, L S Y., Gupta, R C., Randerath, E., Hawkins, E R., Brum, C K., Chang, S H 1975 Biochem Biophys Res Commun 63: 157-68 91 Gillum, A., Urquhart, N., Smith, M., RajBhandary, U L 1975 Cell 2:85-95 92 Gillum, A., Roe, B., Anandaraj, M P J S., RajBhandary,U L 1975 Cell 2: 95-103 92a Chang, S., Hecker, L., Barnett, W., Brum, C., Silberklang, M RajBhandary, U L 1976 Fed Proc In press 93 RajBhandary, U L 1968 J Biol Chem 243:556-64 94 RajBhandary, U L., Stuart, A 1966 Ann Rev Biochem 35:759-88 95 Randerath, K., Chia, L S Y., Gupta, R C., Sivarajan, M 1974 Nucleic Acids Bes 1:1121~[1 96 Simsek, M., Petrissant, G., RajBhandary, U L 1973 Proc Natl Acad Sci USA 70:26~ 97 Sanger, F., Donelson, J E., Carton, A R KiSssel, H., Fischer, D 1973 Proc Natl Acad Sci USA 70:1209-13 98 Fuchs, S., Aharonov,A., Seal, M., von der Haar, F., Cramer, F 1974 Proc Natl Acad Sci USA71:2800-2 99 Szeto, K S., S/511, D 1974 Nucleic Acids Res 1:1733-38 100 Brownlee, G G 1972 Determination of Sequences in RNA,Laboratory Techniques in Biochemistry and Molecular Biology eds T S Work,E Work,Vol 3, Part I, Amsterdam: North Holland; NewYork: American Elsevier 100a Miura, K., Watanabe, K., Sugiura, M 1974 J Mol Biol 86:31 48 101 Barrell, B G., Clark, B F C 1974 Handbook of Nucleic Acid Sequences, Oxford: Joynson-Bruvers L’~d 102 Seidman, J G., Comer, M M., McClain, W H 1974 ,I Mol Biol 90:677-90 103 Harada, F., Sawyer, R C., Dahlberg, J E 1974 J Biol Chem 250:3487-95 104 Piper, P W., Clark, B F C 1974 FEBS Lett 47:56-59 105 Petrissant, G., Boisnard, M 1974 Biochimie 56:787-90 106 Gruhl, H., Feldman, H 1975 FEBS Lett 57:145-48 107 Rogg, H., Miiller, P., Staehelin, M 1975 Eur J Biochem 53:115-27 Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only 856 RICH & RAJBHANDARY 108 Holmes, N J., Atfield, G 1974 FEBS Lett 46:268-70 109 Aksel’rod, V D., Kryukov, V M., Isaenko, S N., Baev, A A 1974 FEBS Lett 45:333-36 110 Penswick, J R., Martin, R., Dirheimer, G 1975 FEBS Lett 50:28-31 111 Kobayashi, T., Irie, T., Yoshida, M., Takeishi, K., Ukita, T 1974 Biochim Biophys Acta 336:168-81 112 Williams, R J., Nagel, W., Roe, B., Dudock, B 1974 Biochem Biophys Res Commun 60:1215-21 113 Kimball, M E., Szeto, K S., S/511, D 1974 Nucleic Acids Res 1:1721-32 114 Clarke, L., Carbon, J 1974 J Biol Chem 249:6874-85 115 Burd, J F., Wells, R D 1974 J Biol Chem 249:7094-7101 116 Chakraburtty, K 1975 Nucleic Acids Res 2:1787-92 117 Yamada, Y., Ishikura, H 1975 FEBS Left 54:155-58 118 Reference deleted in proof 119 Burd, J F., Larson, J E., Wells, R D 1975 J Biol Chem 250:6002-7 120 Adams, A., Lindahl, T., Fresco, J R 1967 Proc Natl Acad Sci USA 57:1684-89 121 Roe, B A., Anandaraj, M P J S., Chia, L S Y., Randerath, E., Gupta, R C., Randerath, K 1975 Biochem Biophys Res Commun.66:1097-1105 122 Faras, A J., Dibble, N A 1975 Proc Natl Acad Sci USA72:859-63 123 Piper, P W., Clark, B F C 1974 Nature 247:516-18 124 Simsek, M., RajBhandary, U L., Boisnard, M., Petrissant, G 1974 Nature 247:518-20 125 Kim, S H., Sussman, J L., Suddath, F L., Quigley, G J., McPherson, A., Rich, A 1974 Proc Natl Aead SeZ USA 71:4970-74 126 Yoshida, M 1973 Biochem Biophys Res Commun 50:779-84 127 Takemura, S., Mizutani, T., Miyazaki, M 1968 J Biochem (Tokyo) 63:277 128 Baev, A A., Fodor, I., Mirzabekov, A D., Aksel’rod, V D., Kazarinova, L Ya 1967 Mol Biol 1:714-23 129 Kim, S H., Suddath, F L., Quigley, G J., McPherson, A., Sussman, J S., Wang,A H J., Seeman,N C., Rich, A 1974 Science 185:435~A3 130 Robertus, J D., Ladner, J E., Finch, J T., Rhodes, D., Brown,R S., Clark, B F C., Klug, A 1974 Nature 250:546-51 131 Clark, B F C., Klug, A 1975 Proc FEBS Meet lOth, pp 183-206 132 Levitt, M 1969 Nature 224:759-63 133 RajBhandary, U L., Chang, S H., Stuart, A., Faulkner, R, D., Hoskinson, R M., Khorana, H G 1967 Proc Natl Acad Sci USA51:751-8 134 Roe, B A., Mignery, R., Marcu, K., Sirover, M., Dudock, B 1973 Biochem Biophys Res Commun.55:477-83 135 Gross, H J., Simsek, M., Raba, M., Limburg, K., Heckman, J., RajBhandary, U L 1974 Nucleic Acids Res 1:35-52 136 Watanabe, K., Oshima, T., Saneyoshi, M., Nishimura, S 1974 FEBS Lett 43:59-63 137 Ladner, J E., Jack, A., Robertus, J D., Brown,R S., Rhodes, D., Clark, B F C., Klug, A 1975 Proc, Natl Acad Sci USA 72:4414-18 138 Hirsh, D 1970 Nature 228:57-58 139 Stewart, T S., Roberts, R J., Strominger, J L 1971 Nature 230:36-38 140 Webb,P., Fresco, J R 1973 J Mol Biol 74:387-402 141 Dube, S K., Marcker, K A., Yudelevich, A 1970 FEBSLett 9:168-70 142 Blank, H U., SiSll, D 1971 Biochem Biophys Res Commun.43:1192-97 143 Dube, S K., Marcker, K A., Clark, B F C., Cory, S 1968 Nature 218: 232-33 144 Riddel, D L., Carbon, J 1973 Nature New Biol 242:230-34 145 Crothers, D M., Cole, P E., Hilbers, C W., Shulman, R G 1974 J Mol Biol 87:63-88 146 Ecarot, B., Cedergren, R J 1974 Biochem Biophys Res Commun 59: 400-5 147 Delk, A S., Rabinowitz, J C 1974 Nature 252:106 148 Walker, R T., RajBhandary, U L 1975 Nucleic Acids Res 2:61-78 149 Olson, T., Fournier, M J., Langley, K H., Ford, N C 1976 / Mol Biol 102:193-204 150 White, B N., Bayley, S T 1972 Biochim Biophys Acta 272:583-87 151 Schulman, L H., Pelka, H 1975 J Biol Chem 250:542-47 152 Simsek, M., RajBhandary, U L 1972 Biochem Biophys Res Commun.49: 508-15 153 Ghosh, K Ghosh, H P., Simsek, M., RajBhandary, U L 1974 J Biol Chem 249:4720-29 154 Arnott, S 1970 Progr Biophys Mol Biol 21:265-319 155 Sobell, H M 1969 Genetic Organization, ed E W Caspari, A W Ravin, pp 91-162 London: Academic Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only STRUCTURE OF TRANSFER RNA 857 156 Voet, D., Rich, A 1970 Progr Nucleic 180 Rosenberg, J., Seeman, N., Day, R O., Rich, A 1976 Biochem Biophys Res Acid Res MoLBiol 10:183-265 Commun 69:979-87 157 Sundaralingam, M 1969 Biopolymers 181 Clark, B F C., Doctor, B P., Holmes, 7:821-60 K C., Klug, A., Marcker, K A., Mor158 Langridge, R., Gomato.s, P J 1963 ris, S J., Paradies, H H 1968 Nature Science 141:694-98 219:122-24 159 Tomita, K., Rich, A 1964 Nature 182 Kim, S H., Rich, A 1968 Science 201:1160-63 162:1381-84 160 Langridge, R., Billeter, M A., Borst, 183 Hampel, A., Labanauskas, M., ConP., Burdon, R H., Weissmann,C 1964 nors, P G., Kirkegard, L., RajBhandProc Natl Acad Sci USA 52:114-19 ary, U L., Sigler, P B., Bock, R M 161 Davies, D R 1967 Ann Rev Biochem 1968 Science 162:1384-86 36:339-64 184 Cramer, F., vonder Haar, F., Saenger, 162 Steiner, R F., Beers, R F 1961 W., Schlimme, E 1968 Angew Chem Polynucleotides Natural and Synthetic 7:895 Nucleic Acids Amsterdam: Elsevier 185 Fresco, J., Blake, R D., Langridge, R 404 pp 1968 Nature 220:1285-87 163 Felsenfeld, G., Miles, H T 1967 Ann, 186 Void, B 1969 Biochem Biophys Res Rev Biochem 36:407~.8 Commun 35:222 164 Arnott, S 1971 Prog Biophys Mol 187 Hampel, A, Bock, R M 1970 BioBiol 22:181-213 chemistry 9:1873-80 165 Felsenfeld, G., Davies, D R., Rich, A 188 Bock, R M., Young, J D., Labanaus1957 J Am Chem Soc 79:2023-24 kas, M., Connors, P G 1969 Cold 166 Hoogsteen, K 1963 Acta Cryst 16: Spring Harbor Symp Quant Biol 907-16 34:149-52 167 Day, R O., Seeman, N C., Rosenberg, J M., Rich, A 1973 Proc Natl Acad 189 Kim, S H., Rich, A 1969 ColdSpring Harbor Symp Quant Biol 34:153-59 ScL USA 70:849-53 168 Stellmon, S D., Hingerty, B., Broyde, 190 Blake, R D., Fresco, J R., Langridge, R 1970 Nature 225:32-35 S B., Subramanian, E., Sato, T., Lan191 Paradies, H H., Sjtiquist, J 1970 Nagridge, R 1973 Biopolymers 12: ture 226:159-61 2731-50 Rosenberg, J M., Seeman, N C., Kim, 192 Kelmers, A D., Stulberg, M P 1970 169 Science 167:237-38 J J., Suddath, F L., Nicholas, H B., 193 Kim, S H., Rich, A 1969 Science Rich, A 1973 Nature 245:150-54 166:1621-24 170 Seeman, N C., Sussman, J L., Berg194 Young, J D., Bock, R M., Nishimura, man, H M., Kim, S H 1971 Nature S., Ishikura, H., Yamada, Y., RajNew Biol 233:90-92 Bhandary, U L., Labanauskas, M., 171 Sussman, J L., Seeman, N C., Kim, Conners, P G 1969 Science 166: S H., Berman,H M 1972 d Mol Biol 1524-28 66:403-20 195 Labanauskas, M., Conners, P G., 172 Rubin, J., Brennan, T., Sundaralingam, Young, J D., Bock, R M., Anderegg, M 1972 Biochemistry 11:3112-28 J W., Beeman, W W 1969 Science 173 Seeman, N C., Day, R O., Rich, A 166:1530-32 1975 Nature 253:324-26 196 Johnson, C D., Adolph, K., Rosa, J J., 174 Tasi, C C., Jain, S C., Sobell, H M Hall, M D., Sigler, P B 1970 Nature 1975 Proc Natl Acad Sci USA 226:1246-47 72:628-32 197 Cramer, F., Sprinzl, R., Furgac, N., Sasisekharan, ¥ 1972 Jerusalem Symp 175 Freist, W., Saenger, W., Manor, P C., Quantum Chem Biochem 5:247-60 Sprinzl, M., Sternbach, H 1974 Bio176 Sundaralingam, M 1972 See Ref 175, chim Biophys Acta 349:351-65 pp 417-56 198 Kim, S H., Quigley, G., Suddath, F L., 177 Kim, S H., Berman, H M., Seeman, McPherson, A., Sneden, D., Kim, J J., N C., Newton, M D 1973 Acta CrysWeinzerl, J., Rich A 1973 J Mol tallogr Sect B 29:703-10 Biol 75:421-28 178 Sasisekharan, V., Sigler, P B 1965 J 199 Cramer, F., Doepner, H., von der Haar, Mol Biol 12:296-98 F., Schlimme, Seidel, H 1968 Proc E., 179 Arnott, S., Dover, S D., Wonacott, Natl Acad Sci USA61:1384-91 A J 1969 Acta Crystallogr Sect B 200 Connors, P G., Labanauskas, M., Bee25:2192-2206 man, W W 1969 Science 166:1528-30 Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only 858 RICH & RAJBHANDARY 201 Fuller, W., Arnott, $., Creek, J 1969 Biochem J 114:26P-27P 202 Melcher, G 1969 FEBSLett 3:185-89 203 Abraham, D J 1971 £ Theor Biol 30:83:91 204 Danchin, A, 1971 FEBS Lett 13: 152-56 205 Cramer, F 1971 Prog Nucleic Acid Res Mol Biol 11:391-421 206 Ninio, J., Favre, A., Yaniv, M 1969 Nature 223:1333-35 207 Favre, A., Yaniv, M., Michelson, A M 1969 Biochem Biophys Res Commun 37:266-71 208 Kim,S H., Quigley, G., Sudd[th, F L., Rich, A 1971 Proc.Natl ,4cad Sci USA 68:841-45 209 Cramer, F., vonder Haar, F., Holmes, K C., Saenger, W., Schlimme, E., Schuly, G E 1970 J MoLBiol 51: 523 210 Ichikawa, T,, Sundaralingam, M 1972 Nature New Biol 236:174-75 211 Ladner, J E., Finch, J T., Klug, A., Clark, B F C 1972 J MoL Biol 72:99-101 212 Brown,R S., Clark, B F C., Coulson, R R., Finch, J T., Klug, A., Rhodes, D 1972 Eur J Biochem 3t:130-34 213 Omilianowski, D R 1971 PhDthesis Univ Wisconsin, Madison 281 pp 214 Schmidt, F J., Omilianowski, D R., Bock, R M 1973 Biochemistry 12: 4980-83 215 Sprinzl, M., von der Haar, F., Schlimme, E., Sternbach, H., Cramer, F 1972 Eur ,L Biochem 25:262-66 216 Pasek, M., Vettkatappa, M P., Sigler, P B 1973 Biochemistry 12:4834-40 217 Dale, R M K., Livingston, D C., Ward,D C 1973 Proc Natl Acad Sci USA 70:2238-42 218 Schlimme, E., vonder Haar, F., Eckstein, F Cramer, F 1970 Eur J Biochem 14:351-56 219 Sprinzl, M., Scheit, K H., Cramer, F 1973 Eur J Biochem 34:306-10 220 Schevitz, R W et al 1972 Science 177: 429-31 221 Rosa, J J., Sigler, P B 1974 Biochemistry 13:5102-9 222 Kim, S H., Quigley, G., Suddath, F L., McPherson,A., Sneden, D., Kim, J J., Weinzerl, J., Blattmann, P., Rich, A 1972 Proc NatL Acad Sci USA 69:3746-50 223 Suddath, F L., Quigley, G J., McPherson, A., Sneden, D., Kim, L J., Kim, S H., Rich, A 1974 Nature 248:20-24 224 Conn, J F., Kim,J J., Suddath, F L., Blattmann, P., Rich, A 11974 J Am Chem Soc 96:7152-53 225 Kayne, M S., Cohn, M 1972 Biochem Biophys Res Commun.46:1285-91 226 Kayne, M S., Cohn, M 1974 Biochemistry 13:4159-65 227 Rhodes, D., Piper, P W., Clark, B F C 1974, £ MoLBiol 89:467-75 228 Kim, S H., Quigley, G., Suddath, F L., McPherson, A., Sneden, D., Kim, J J., Weinzerl, J., Rich, A 1973 J MoL BioL 75:429-32 229 Quigley, G J., Suddath, F L., McPherson, A., Kim,J J., Sneden, D., Rich, A 1974 Proc Natl Acad Sci USA 71:2146-50 230 Klug, A,, Robertus, J D., Ladner, J E., Brown,R S., Finch, J T 1974 Proc Natl Acad Sci USA 71:3711-15 231 Quigley, G J., Wang,A H-J., Seeman, N C., Suddath, F L., Rich, A., Sussman,J L., Kim, S H 1975 Proc Natl Acad Sci USA 72:4866-70 232 Crick, F H C 1966 J Mol BioL 19:548-55 233 Yang, S., Reinitz, E R., Gefter, M L 1973 Arch Biochem Biophys 157: 55-62 234 Gartland, G L., Craven, B M 1974 Acta Cryst 330:980-87 235 Klug, A., Ladner, J., Robertus, J D 1974 £ Mol BioL 89:511-16 236 Bergstrom, D E., Leonard, N J 1972 Biochemistry 11:1-8 237 Rich, A., Davies, D R., Crick, F H C., Watson, J D 1961 £ MoL BioL 3:71-86 238 Kim, S H., Rich, A 1968 Proc Natl Acad Sci USA 60:402-8 239 Fuller, W., Hodgson, A 1967 Nature 215:817-21 240 Schevitz, R W., Krishnamachari, N., Hughes, J., Rosa, J., Pasek, M., Cornick, G., Navia, M A., Sigler, P B 1975 Structure and Conformation of Nucleic Acids and Protein-Nucleic Acid Interactions Proc Ann Harry Steenhock Syrup., 4th, ed M Sundaralingam, S T Rao Baltimore: Univ Park Press, p xx, pp 776 241 Richter, D., Erdmann, V A., Sprinzl, M 1973 Nature NewBiol 246:132-35 242 Erdmann, ¥ A., Sprinzl, M., Pongs, O 1973 Biochem Biophys Res Commun 54:942-48 243 Robertus, J D., Ladner, J E., Finch, J T., Rhodes, D., Brown,R S., Clark, B F C., Klug, A 1974 Nucleic Acids Res 1:927-34 Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only STRUCTURE OF TRANSFER RNA 244 Harbers, K., Thiebe, R., Zachau, H G 1972 Eur.J Biochem 26:132-143 245 Gamble, R C., Schimmel, P R 1974 Proc Natl Acad Sci USA71:1356-60 246 Uhlenbeck, O C., Bailer, J., Doty, P 1970 Nature 225:508-510 247 Yang, C-H., SiSll, D 1974 Proc Natl Acad Sci USA 71:2838-42 248 Chen, M C., Geige, R., Lord, R C., Rich, A 1975 Biochemistry 14: 4385-91 249 Rhodes, D 1975 J Mol Biol 94:449460 250 Litt, M 1969 Biochemistry 8:3249-53 251 Pilz, 1., Kratky, O., Cramer,F., vonder Haar, F., Schlimme, E 1970 Eur J Biochem 15:401-9 252 Cashmore, A R., Brown, D M., Smith, J D 1971 J Mol Biol 59:395-473 253 Ho, N W Y., Gilham, P T 1967 Biochemistry 6:3632-39 254 Chang, S E 1973 J Mol Biol 75:533-47 255 Igo-Kimenes, T., Zachau, H G 1971 Eur J Biochem 18:459-56 256 Igo-Kimenes,18:292-98 H 1971 Eur J Biochem T., Zachau, 257 Commerford,S L 1971 Biochemistry 10:1993-2000 258 Batey, I L., Brown, D M 1975 Mol Biol Rep 2:65-72 259 Litt, M 1971 Biochemistry 10:2223-26 260 Wintermeyer, W., Zachau, H G 1975 FEBS Lett 58:306-9 261 Chang, S E., Cashmore, A R., Brown, D M 1972 J Mol Biol 68:455-565 262 Chang,S E., Ish-Horowicz, D 1974 J Mol Biol 84:375-88 263 Piper, P W., Clark, B F C 1974 Nucleic Acids Res 1:45-51 264 Cashmore, A R 1971 Nature New Biol 230:236-39 265 Hawkins, E R., Chang, S H 1974 Nucleic Acids Res, 1:1531-38 266 Litt, M., Greenspan, C 1972 Biochemistry 11:1437-42 267 Favre, A., Buckingham, R., Thomas, G 197L Nucleic Acids Res 2:142l-3l 268 Greenspan, C., Litt, M 1974 FEBS Lett 41:297-302 269 Zhilyaeva, T I., Kiselev, L L 1970 FEBS Lett 10:229-32 R W., Aoyagi, S., 270 Chambers, Furukawa, Y., Zawadzka, A., Bhanot, O S 1973 J Biol Chem.248:5549-51 271 Singhal, R P 1974 Biochemistry 13:2924-31 272 Fijimura, S., Grunberger, D., Carvajal, G., Weinstein, I B 1972 Biochemistry 11:3629-35 859 273 Pulkrabek, P., Grunberger, D., Weinstein, I B 1974 Biochemistry 13: 2414-19 274 Kearns, D R., Shulman, R G 1974 Ace Chem Res 7:33-39 275 Kearns, D R., Patel, D., Shulman, R G 1971 Nature 229:338-39 276 Kearns, D R., Patel, D., Shulman, R G., Yamane, T 1971 J Mol Biol 61:265-70 277 Crothers, D M., Hilbers, C W., Shulman, R G 1973 Proc Natl Acad Sci US/t 70:2899-2901 278 Shulman, R G., Hilbers, C W., Kearns, D R., Reid, B R., Wong,Y P 1973 J Mol Biol 78:57-60 279 Lightfoot, D R., Wong,K L., Kearns, D R., Reid, B R., Shulman, R G 1973 J Mol Biol 78:71-89 280 Reid, B R., Robillard, G T 1975 Nature 257:287-91 281 Reid, B R., Ribeiro, N S., Gould, G., Robillard, G., Hillers, C W., Shulman, R G 1975 Proc Natl Acad Sci USA 72:2049-53 282 Daniel, W E., Jr., Cohn, M 1975 Proc Natl Acad Sci USA 72:2582-86 283 Wong, K L., Kearns, K R 1974 Nature 252:738-39 284 Saneyoshi, M., Nishimura, S 1967 Biochim Biophys Acta 145:208-10 285 Wong, K L, Bolton, P H., Kearns, D R 1975 Biochim Biophys Acta 383:446-51 286 Bolton, P H., Kearns, D R 1975 Nature 255:347-49 287 Penswick, J R., Holley, R W 1965 Proc Natl Acad Sci USA 53:543-46 288 Zachau, H ~., Dutting, D., Feldmann, H., Melchers, F., Karau, W 1966 Cold Spring Harbor Symp Quant Biol 31:417-24 289 Madison, J T., Kung, H~K 1967 J Biol Chem 242:1324-30 290 Chang, S Chem 243:529-57 U L 1968 J Biol H., RajBhandary, 291 Armstrong, A., Hagopian, H., Ingram, V M., Wagner, E 1966 Biochemistry 5:3027-36 292 Seno, T., Kobayashi, M., Nishimura, S 1969 Biochim Biophys Acta 182: 280-82 293 Seno, T., Kobayashi, M., Nishimura, S 1969 Biochim Biophys Acta 174: 408-11 294 Schmidt, J., Buchardt, B., Reid, B R 1970 J Biol Chem 245:5743-50 295 Samuelson,G., Keller, E B 1972 Biochemistry 11:30-35 296 Rich, A 1971 See Ref 22, pp 161-84 Annual Reviews www.annualreviews.org/aronline Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only 860 RICH & RAJBHANDARY 297 Streeck, R E., Zachau, H G 1971 FEBS Lett 13:329-34 298 Streeck, R E., Zachau, H G 1972 Eur J Biochem 30:382-91 299 Woese, C 1970 Nature 226:817-20 300 HiSgenauer, G 1970 Eur J Biochem 12:527 301 Freier, S M., Tinoco, I Jr 1975 Biochemistry 14:3310-14 302 Pongs, O., Reinwald, E., Stamp, K 1971 FEBS Lett 16:275-77 303 Pongs, O., Reinwald, E 1973 Biochem Biophys Res Commun.50:357-63 304 Eisinger, J., Feuer, B., Yamane, T 1971 Nature NewBiol 231:126-28 305 Eisinger, J., Spahr, P 1973 J MoLBioL 73:131-37 306 Cameron, V., Uhlenbeck, O C 1973, Biochem Biophys Res Commun 50:6352v0 307 Miller, P S., Barrett, J C., Ts’o, P O P 1974 Biochemistry 13:4887-96 308 Pongs, O., Bald, R., Reinwald, E 1973 Eur J Biochem 32:117-25 309 Uhlenbeck, O C., Chirikjian, J G., Fresco, J R 1974 J Mol BioL 89:495504 310 Uhlenbeck, O C 1972 J MoLBioL 65:25 41 311 Hogenauer, G., Turnowsky, F., Unger, F M 1972 Biochem Biophys Res Commun 46:2100-06 312 Schimmel, P R., Uhlenbeck, O C., Lewis, J B., Dickson, L A., Eldred, E W., Schreier, A A 1972 Biochemistry 11:642-46 313 Schwartz, I., Ofengand, J 1974 Proc NatL Acad Sci USA 71:3951-55 314 Wong,Y P., Reid, B R., Kearns, D R 1973 Proc Natl Acad Sci USA 70:2093-95 315 Kan, L S., Ts’o, P O P., Sprinzl, M., van der Haar, F., Cramer, F 1976 Biophys £ 16:lla 316 Fraser, T H., Rich, A 1973 Proc NatL Acad ScL USA 70:2671-75 317 Schwarz, U., Liihrmann, R., Gassen, H G 1974 Biochem Biophys Res Commun 56:807-14 318 Schwarz, U., Menzel, H M., Gassen, H G 1976 Biochemistry In press 319 Richter, D., Erdmann, V A., Sprinzl, M 1974 Proc NatL Acad Sci USA 71:3226-29 320 Grummt, F., Grummt,I, Gross, H J., Sprinzl, M., Richter, D., Erdmann, V A 1974 FEBS Lett 42:15-17 Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only Annu Rev Biochem 1976.45:805-860 Downloaded from arjournals.annualreviews.org by Columbia University on 01/24/07 For personal use only ... University on 01/24/07 For personal use only Aminoacyl-tRNA Transferases Aminoacyl-tRNA transferases are a group of enzymes that catalyze the transfer of an amino acid from aa-tRNAto specific acceptor... tRNAmeansthat we are now in a position to ask intelligent questions about the molecular dynamicsof this biological function, Transfer RNA involved in a large numberof biological processes and it would... numberof ribosomal proteins including the peptidyl transferase before it is finally released from the ribosome after its aminoacid has been transferred to the growingpolypeptide chain of an adjacent