文摘
Staphylococcus aureus grown in the presence of an alanine-racemase inhibitor was labeled with d-[1-13C]alanine and l-[15N]alanine to characterize some details of the peptidoglycan tertiary structure. Rotational-echo double-resonance NMR of intact whole cells was used to measure internuclear distances between 13C and 15N of labeled amino acids incorporated in the peptidoglycan, and from those labels to 19F of a glycopeptide drug specifically bound to the peptidoglycan. The observed 13C鈥?sup>15N average distance of 4.1鈥?.4 脜 between d- and l-alanines in nearest-neighbor peptide stems is consistent with a local, tightly packed, parallel-stem architecture for a repeating structural motif within the peptidoglycan of S. aureus.