Crystal structure of human peptidoglycan recognition protein Iα bound to a muramyl pentapeptide from Gram-positive bacteria

Rongjin Guan, Patrick H. Brown, Chittoor P. Swaminathan, Abhijit Roychowdhury, Geert Jan Boons, Roy A. Mariuzza*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Peptidoglycan recognition proteins (PGRPs) are pattern recognition receptors of the innate immune system that bind bacterial peptidoglycans (PGNs). We determined the crystal structure, to 2.1 Å resolution, of the C-terminal PGN-binding domain of human PGRP-Iα in complex with a muramyl pentapeptide (MPP) from Gram-positive bacteria containing a complete peptide stem (L-Ala-D-isoGln-L-Lys-D-Ala-D-Ala). The structure reveals important features not observed previously in the complex between PGRP-Iα and a muramyl tripeptide lacking D-Ala at stem positions 4 and 5. Most notable are ligand-induced structural rearrangements in the PGN-binding site that are essential for entry of the C-terminal portion of the peptide stem and for locking MPP in the binding groove. We propose that similar structural rearrangements to accommodate the PGN stem likely characterize many PGRPs, both mammalian and insect. Published by Cold Spring Harbor Laboratory Press.

Original languageEnglish
Pages (from-to)1199-1206
Number of pages8
JournalProtein Science
Volume15
Issue number5
DOIs
Publication statusPublished - 1 May 2006
Externally publishedYes

Keywords

  • Bacteria
  • Crystal structure
  • Innate immunity
  • Peptidoglycan
  • PGRP

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