Staphylococcus aureus peptidoglycan tertiary structure from carbon-13 spin diffusion.
The cell-wall peptidoglycan of Staphylococcus aureus is a heterogeneous, highly cross-linked polymer of unknown tertiary structure. We have partially characterized this structure by measuring spin diffusion from (13)C labels in pentaglycyl cross-linking segments to natural-abundance (13)C in the surrounding intact cell walls. The measurements were performed using a version of centerband-only detection of exchange (CODEX). The cell walls were isolated from S. aureus grown in media containing [1-(13)C]glycine. The CODEX spin diffusion rates established that the pentaglycyl bridge of one peptidoglycan repeat unit of S. aureus is within 5 A of the glycan chain of another repeat unit. This surprising proximity is interpreted in terms of a model for the peptidoglycan lattice in which all peptide stems in a plane perpendicular to the glycan mainchain are parallel to one another.
Sharif
Shasad
S
Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA.
Singh
Manmilan
M
Kim
Sung Joon
SJ
Schaefer
Jacob
J
D002236:Carbohydrate Conformation; D002247:Carbon Isotopes; D002473:Cell Wall / Q000737:chemistry; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D010457:Peptidoglycan / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000737:chemistry*
D002247:Carbon Isotopes; D010457:Peptidoglycan