On the process of cellular division in Escherichia coli: isolation and characterization of penicillin-binding proteins 1a, 1b, and 3.

Abstract

Multiple mutants of Escherichia coli defective in penicillin-bindingproteins (PBPs) were constructed, and into these strains CoEl plasmids carrying the genes for PBP-la, -lb, or -3 were introduced. From these plasmid-carrying strains, PBP-la and -lb were purified by ampicillin-Sepharose affinity chromatography and PBP-3 by cephalexin-Sepharose affinity chromatography. Improved purification was achieved by differential elution with NH20H. Purified PBP-lb synthesized murein when added to the membrane fraction of a PBP-lbdefective mutant, which by itself failed to support murein synthesis in vitro. The PBP-lb preparation was able to synthesize murein from the lipid intermediate extracted with chloroform/methanol but was unable to utilize UDP4inked precursors for murein synthesis. Murein synthesis was inhibited by van-comysin, ristocetin, moenomycin, and enduracidin, but not by f-lactam antibiotics. The synthesized murein was shown to contain crosslinked muropeptides. Their crosslinking was abolished by action of ,-lactam antibiotics. The PBP-la and -3 preparations showed substantially no activity for murein synthesis in the same reaction system. None of the three PBPs showed D-alanine carboxypeptidase activity with UDP-Nacetylmuramoyl-ntapeptide as substrate or endopeptidase activity with bis(dsaccharidepeptide) as substrate.

Antibacterial activity of synthetic analogues based on the disaccharide structure of moenomycin, an inhibitor of bacterial transglycosylase

“…coli (Hara & Suzuki, 1984 ;Kohlrausch & Holtje, 1991a ;Tamura et al, 1980 ;van Heijenoort et al, 1978van Heijenoort et al, , 1987van Heijenoort & van Heijenoort, 1980). Moenomycin is rapidly bactericidal to growing Esc.…”

Cell-wall recycling and synthesis in Escherichia coli and Pseudomonas aeruginosa – their role in the development of resistance

“…High molecular mass penicillin-binding proteins (HMM PBPs) with a transglycosylase domain (PBP1A, PBP1B and PBP1C) facilitate the link between the MurNAc end of lipid II with the GlcNAc of the existing strand [45][46][47][48][49][50]. HMM PBPs with a transpeptidase domain (PBP1A, PBP1B, PBP1C, PBP2 and PBP3) catalyse the formation of cross-links between two peptide chains [47,[51][52][53][54] (Table 1).…”

A Role in vivo for Penicillin‐Binding Protein‐4 of Staphylococcus aureus

“…In this organism distinct penicillinbinding proteins have been implicated in the determination of cell shape [4,5] ; cell division [6] and elongation [4,5,7,8]. With the exception of penicillin-binding protein 2, all have now been isolated and purified [9-141 and in the case of protein 1A [I21 and 1B [9,10,13] shown to catalyse in vitro transglycosylation and transpeptidation reactions using lipid intermediates as the peptidoglycan precursors. The lower molecular weight proteins (4, 5 and 6) catalyse DD-carboxypeptidase and in the case of proteins 5 and 6 'model' transpeptidase activity [I 1,141.…”