Structural insights into the loss of penicillinase and the gain of ceftazidimase activities by OXA-145 β-lactamase in<i>Pseudomonas aeruginosa</i>

Abstract

Deletion of Leu-155 resulted in inefficient positioning of Trp-154, leading to a non-carboxylated Lys-70 and thus to loss of hydrolysis of the penicillins. Ceftazidime hydrolysis could be attributed to enlargement of the active site and to a catalytic mechanism independent of the carboxylated Lys-70.