... fragments of M-OmpA and I-OmpA displayed a band at a molecular mass of 7 kDa (Fig. 2A, lanes 1and 2), identified by N-terminal sequencing as frag-ment 264–325 (6.6 kDa). A western blot of a similargel ... (Beckman SS 34 rotor) at 4 °C. His–OmpA wasextracted and purified by Ni2+–agarose chromatography asdescribed by the manufacturer (Qiagen, Valencia, CA,USA). Alternatively, His–OmpA was extracted ... (Avanti Polar Lipids, Alabaster, AL, USA).Planar lipid bilayers were formed from a solution of DPhPC in n-decane (Sigma-Aldrich, Union City, CA,USA) at a concentration of 17 mgÆmL )1 . The...