1zat
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(New page: 200px<br /><applet load="1zat" size="450" color="white" frame="true" align="right" spinBox="true" caption="1zat, resolution 2.40Å" /> '''Crystal Structure of...)
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Revision as of 02:40, 25 November 2007
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Crystal Structure of an Enterococcus faecium peptidoglycan binding protein at 2.4 A resolution
Overview
During the final stages of cell-wall synthesis in bacteria, penicillin-binding proteins (PBPs) catalyse the cross-linking of peptide, chains from adjacent glycan strands of nascent peptidoglycan. We have, recently shown that this step can be bypassed by an L,D-transpeptidase, which confers high-level beta-lactam-resistance in Enterococcus faecium., The resistance bypass leads to replacement of D-Ala4-->D-Asx-L-Lys3, cross-links generated by the PBPs by L-Lys3-->D-Asx-L-Lys3 cross-links, generated by the L,D-transpeptidase. As the first structure of a member of, this new transpeptidase family, we have determined the crystal structure, of a fragment of the L,D-transpeptidase from E.faecium (Ldt(fm217)) at, 2.4A resolution. Ldt(fm217) consists of two domains, the N-terminal, domain, a new mixed alpha-beta fold, and the ErfK_YbiS_YhnG C-terminal, domain, a representative of the mainly beta class of protein structures., Residue Cys442 of the C-terminal domain has been proposed to be the, catalytic residue implicated in the cleavage of the L-Lys-D-Ala peptide, bond. Surface analysis of Ldt(fm217) reveals that residue Cys442 is, localized in a buried pocket and is accessible by two paths on different, sides of the protein. We propose that the two paths to the catalytic, residue Cys442 are the binding sites for the acceptor and donor substrates, of the L,D-transpeptidase.
About this Structure
1ZAT is a Single protein structure of sequence from Enterococcus faecium with ZN and SO4 as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structure of a novel beta-lactam-insensitive peptidoglycan transpeptidase., Biarrotte-Sorin S, Hugonnet JE, Delfosse V, Mainardi JL, Gutmann L, Arthur M, Mayer C, J Mol Biol. 2006 Jun 9;359(3):533-8. Epub 2006 Mar 23. PMID:16647082
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