Conformational and quantitative characterization of oritavancin-peptidoglycan complexes in whole cells of Staphylococcus aureus by in vivo 13C and 15N labeling.
Solid-state NMR has been used to examine the cell walls of intact whole cells of Staphyloccus aureus grown on media containing D-[1-(13)C]alanine, [(15)N]glycine, and the alanine racemase inhibitor, alaphosphin. The results of in situ site-selective, four-frequency NMR experiments show directly for the first time that (i) 54% of the cell-wall peptidoglycan stems have D-alanine termini and 46%, D-alanine-D-alanine termini; (ii) the molar ratio of stems ending in D-alanine to esterified alditol repeats of cell-wall teichoic and lipoteichoic acids is 3:2; and (iii) 50% of the mature cell-wall binding sites for a fluorinated oritavancin analogue consist of two nearest-neighbor peptide stems of different glycan strands. The drug is bound to the D-Ala-D-Ala terminus of one stem and is proximate to the bridging pentaglycyl segment that cross-links the two stems. Structural details of the binding site are revealed in a model of the glycopeptide-peptidoglycan interaction produced by molecular dynamics simulations with internuclear distance restraints determined by NMR.
Department of Chemistry, Washington University, St. Louis, MO 63130, USA.
Lynette
L
Cegelski
Dirk
D
Steuber
Anil K
AK
Mehta
Daniel W
DW
Kulp
Paul H
PH
Axelsen
Jacob
J
Schaefer
D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000378:metabolism; D001665:Binding Sites; D002247:Carbon Isotopes / Q000737:chemistry* / Q000378:metabolism; D002473:Cell Wall / Q000737:chemistry; D006020:Glycopeptides / Q000737:chemistry* / Q000378:metabolism; D000077427:Lipoglycopeptides; D008958:Models, Molecular; D015394:Molecular Structure; D009587:Nitrogen Isotopes / Q000737:chemistry* / Q000378:metabolism; D019906:Nuclear Magnetic Resonance, Biomolecular; D010457:Peptidoglycan / Q000737:chemistry* / Q000378:metabolism; D013211:Staphylococcus aureus / Q000737:chemistry* / Q000378:metabolism; D014640:Vancomycin / Q000031:analogs & derivatives
D000900:Anti-Bacterial Agents; D002247:Carbon Isotopes; D006020:Glycopeptides; D000077427:Lipoglycopeptides; D009587:Nitrogen Isotopes; D010457:Peptidoglycan; C100708:oritavancin; D014640:Vancomycin