Binding of thienamycin and clavulanic acid to the penicillin-binding proteins of Escherichia coli K-12.

Thienamycin and clavulanic acid are new beta-lactam derivatives with structures markedly different from those of penicillins or cephalosporins. Both derivatives had the same general mode of action as typical beta-lactam antibiotics since they bound to precisely the same proteins as [(14)C]benzylpenicillin. Thienamycin showed high affinity for penicillin-binding proteins 1, 2, 4, 5, and 6 and a lower affinity for protein 3.

Temperature-sensitive cell division mutants of Escherichia coli with thermolabile penicillin-binding proteins.

The thermostability of the penicillin-binding proteins (PBPs) of 31 temperature-sensitive cell division mutants of Escherichia coli has been examined. Two independent cell division mutants have been found that have highly thermolabile PBP3. Binding of [(14)C]benzylpenicillin to PBP3 (measured in envelopes prepared from cells grown at the permissive temperature) was about 30% of the normal level at 30 degrees C, and the ability to bind [(14)C]benzylpenicillin was rapidly lost on incubation at 42 degrees C.

Properties of the penicillin-binding proteins of Escherichia coli K12,

Benzyl[14C]penicillin binds to six proteins with molecular weights between 40000 and 91000 in the inner membrane of Escherichia coli. Two additional binding proteins with molecular weights of 29000 and 32000 were sometimes detected. All proteins were accessible to benzyl[14C]penicillin in whole cells.

Comparison of the binding properties of two 6 beta-amidinopenicillanic acid derivatives that differ in their physiological effects on Escherichia coli.

The 6-beta-amidinopenicillanic acid derivative, mecillinam, was highly specific in its action on the growth of Escherichia coli. Concentrations from the minimal inhibitory concentration (0.05 mug/ml) up to at least 200 mug/ml resulted in the conversion of E.

Identification of the major penicillin-binding proteins of Escherichia coli as D-alanine carboxypeptidase IA.

Penicillin-binding proteins 5 and 6 of Escherichia coli have been identified as d-alanine carboxypeptidase IA.

Distinct penicillin binding proteins involved in the division, elongation, and shape of Escherichia coli K12.

The varied effects of beta-lactam antibiotics on cell division, cell elongation, and cell shape in E. coli are shown to be due to the presence of three essential penicillin binding proteins with distinct roles in these three processes. (A) Cell shape: beta-Lactams that specifically result in the production of ovoid cells bind to penicillin binding protein 2 (molecular weight 66,000).