The ponA gene of cosmid L222 of the Mycobacterium leprae genome librar
y encodes a multimodular class A penicillin-binding protein (PBP), PBP
1. The PBP, labelled with a polyhistidine sequence, has been produced
in Escherichia coli, extracted from the membranes with lamidopropyl)-
dimethylammonio]-1-propane-sulfonate (CHAPS) and purified by Ni2+-nitr
ilotriacetic acid-agarose chromatography. In contrast to the pon1-enco
ded class A PBP1, PBP1 undergoes denaturation at temperatures higher
than 25 degrees C, it catalyzes acyl transfer reactions on properly st
ructured thiolesters, and it binds penicillin with high affinity.