1twq
From Proteopedia
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Crystal structure of the C-terminal PGN-binding domain of human PGRP-Ialpha in complex with PGN analog muramyl tripeptide
Overview
Peptidoglycan (PGN) recognition proteins (PGRPs) are pattern-recognition receptors of the innate immune system that bind and, in some cases, hydrolyze bacterial PGNs. We determined the crystal structure, at 2.30-A resolution, of the C-terminal PGN-binding domain of human PGRP-Ialpha in complex with a muramyl tripeptide representing the core of lysine-type PGNs from Gram-positive bacteria. The peptide stem of the ligand is buried at the deep end of a long binding groove, with N-acetylmuramic acid situated in the middle of the groove, whose shallow end can accommodate a linked N-acetylglucosamine. Although most interactions are with the peptide, the glycan moiety also seems to be essential for specific recognition by PGRPs. Conservation of key PGN-contacting residues shows that all PGRPs employ this basic PGN-binding mode. The structure pinpoints variable residues that likely mediate discrimination between lysine- and diaminopimelic acid-type PGNs. We also propose a mechanism for PGN hydrolysis by Zn(2+)-containing PGRPs.
About this Structure
1TWQ is a Single protein structure of sequence from Homo sapiens with and as ligands. Full crystallographic information is available from OCA.
Reference
Structural basis for peptidoglycan binding by peptidoglycan recognition proteins., Guan R, Roychowdhury A, Ember B, Kumar S, Boons GJ, Mariuzza RA, Proc Natl Acad Sci U S A. 2004 Dec 7;101(49):17168-73. Epub 2004 Nov 30. PMID:15572450
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