... Ca of Glu and itscarboxylate oxygen, Ca of Asp a nd its carboxylate oxygen,Ca of Arg and its side-chain amines or guanidinium, and Ca of Lys and its side-chain amine was determined bymeasuring ... the active site by the interaction of t heN-terminal amine of t he P1 residue with a c arboxylateoxygen of Asp273 (Asp366), the carbonyl oxygen of the P1residue with the side-chain amine of ... the edge of an eight-stranded, saddle-shaped b shee t. In the blLAP, the freelyexchanging zinc ion (Zn1; Zn488) is coordinated by the carboxylate oxygens of Asp255, Asp332 and Glu334, and the...