Search

Transition-state analog complex crystal structure of the phosphonate derivative of Enterobacter cloacae P99 cephalosporinase is homologous to the tetrahedral intermediate structure in beta-lactamase catalysis. The Tyr 150 hydroxyl group is preferred as an acid/base catalyst in the beta-lactamase active site. The sensitivity of serine beta-lactamases is opposite to that of serine proteases in phosphonate monoanion inhibition and indicates a positive potential in the catalytic sites.

Acylated activating elements, precatalytic structures and acyl-enzyme intermediates for sulbactam are produced from the crystal structure of class A-beta lactamases of Bacillus licheniformis. Sulbactam functions as a mechanism-based lactamase inactivator of the Lys-234, Lys-73 and Ser-130 residues. The leaving group penicillanic acid does not affect inactivation rate.