Vancomycin

Vancomycin is a glycopeptide antibiotic discovered by Mack McCormick in 1955. Vancomycin is a transpeptidase analog. It binds to the terminal (D-ala)-(D-ala) residues on the peptidoglycan tetrapeptide, thereby preventing transpeptidase from binding and forming the tetrapeptide linkage. Vancomycin can be spectrophotometrically detected on the cell wall in a cell wall extract after sonication. More directly, BODIPY-tagged vancomycin can be visualized bound to the cell wall using phase contrast/fluorescent microscopy. In vitro, the binding of vancomycin to (D-ala)-(D-ala) can be confirmed by fluorometric titration against dansylated (D-ala)-(D-ala). X-ray crystallography can also be used to visualize the (D-ala)-(D-ala)-vancomycin complex. Vancomycin resistance evolves through D-ala \( \rightarrow \) D-lac substitutions in the cell wall tetrapeptide.