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Publication Abstract from PubMed

The cell wall imparts structural strength and shape to bacteria. It is made up of polymeric glycan chains with peptide branches that are cross-linked to form the cell wall. The cross-linking reaction, catalyzed by transpeptidases, is the last step in cell wall biosynthesis. These enzymes are members of the family of penicillin-binding proteins, the targets of beta-lactam antibiotics. We report herein the structure of a penicillin-binding protein complexed with a cephalosporin designed to probe the mechanism of the cross-linking reaction catalyzed by transpeptidases. The 1.2-A resolution x-ray structure of this cephalosporin bound to the active site of the bifunctional serine type D-alanyl-D-alanine carboxypeptidase/transpeptidase (EC ) from Streptomyces sp. strain R61 reveals how the two peptide strands from the polymeric substrates are sequestered in the active site of a transpeptidase. The structure of this complex provides a snapshot of the enzyme and the bound cell wall components poised for the final and critical cross-linking step of cell wall biosynthesis.

A 1.2-A snapshot of the final step of bacterial cell wall biosynthesis.,Lee W, McDonough MA, Kotra L, Li ZH, Silvaggi NR, Takeda Y, Kelly JA, Mobashery S Proc Natl Acad Sci U S A. 2001 Feb 13;98(4):1427-31. PMID:11171967^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.