Three-dimensional structure of the bacterial cell wall peptidoglycan

Samy O. Meroueh, Krisztina Z. Bencze, Dusan Hesek, Mijoon Lee, Jed F. Fisher, Timothy L. Stemmler, Shahriar Mobashery

Research output: Contribution to journalArticle

250 Scopus citations

Abstract

The 3D structure of the bacterial peptidoglycan, the major constituent of the cell wall, is one of the most important, yet still unsolved, structural problems in biochemistry. The peptidoglycan comprises alternating N-acetylglucosamine (NAG) and N-acetylmuramic disaccharide (NAM) saccharides, the latter of which has a peptide stem. Adjacent peptide stems are cross-linked by the transpeptidase enzymes of cell wall biosynthesis to provide the cell wall polymer with the structural integrity required by the bacterium. The cell wall and its biosynthetic enzymes are targets of antibiotics. The 3D structure of the cell wall has been elusive because of its complexity and the lack of pure samples. Herein we report the 3D solution structure as determined by NMR of the 2-kDa NAG-NAM(pentapeptide)-NAG-NAM(pentapeptide) synthetic fragment of the cell wall. The glycan backbone of this peptidoglycan forms a right-handed helix with a periodicity of three for the NAG-NAM repeat (per turn of the helix). The first two amino acids of the pentapeptide adopt a limited number of conformations. Based on this structure a model for the bacterial cell wall is proposed.

Original languageEnglish (US)
Pages (from-to)4404-4409
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume103
Issue number12
DOIs
StatePublished - Mar 21 2006

Keywords

  • Bacterial envelope
  • Murein sacculus

ASJC Scopus subject areas

  • General

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