AFFINITIES OF PENICILLINS AND CEPHALOSPORINS FOR THE PENICILLIN-BINDING PROTEINS OF ESCHERICHIA-COLI K-12 AND THEIR ANTIBACTERIAL ACTIVITY

The affinities of a range of penicillins and cephalosporins for their penicillin-binding proteins of E. coli K-12 have been studied, and the results were compared with the antibacterial activity of the compounds against E. coli K-12 and an isogenic permeability mutant. Different penicillins and cephalosporins exhibited different affinities for the 'essential' penicillin-binding proteins of E. coli K-12, in a manner which directly correlated with their observed effects upon bacterial morphology. Furthermore, the affinities of the compounds for their 'primary' lethal penicillin-binding protein targets showed close agreement with their antibacterial activities against the permeability mutant.