Vancomycin mechanism involves attacking which crossbridges in the peptidoglycan?

Vancomycin mechanism involves attacking which crossbridges in the peptidoglycan?

• A. Glycosidic linkages in peptidoglycan
• B. Alanine-alanine crossbridges between NAMs
• C. DNA gyrase
• D. RNA polymerase

Answer: (B)

Vancomycin works by binding to the D-Ala-D-Ala end of the peptidoglycan peptide chains, which blocks the formation of the peptide crossbridges that connect NAM-containing strands. Those crossbridges are the alanine-alanine links between different peptidoglycan stems; when vancomycin occupies the D-Ala-D-Ala terminus, transpeptidation and crosslinking can’t occur, weakening the cell wall and halting proper wall synthesis. This mechanism targets the peptide crosslinks, not the glycosidic bonds, and not enzymes like DNA gyrase or RNA polymerase.

Vancomycin works by binding to the D-Ala-D-Ala end of the peptidoglycan peptide chains, which blocks the formation of the peptide crossbridges that connect NAM-containing strands. Those crossbridges are the alanine-alanine links between different peptidoglycan stems; when vancomycin occupies the D-Ala-D-Ala terminus, transpeptidation and crosslinking can’t occur, weakening the cell wall and halting proper wall synthesis. This mechanism targets the peptide crosslinks, not the glycosidic bonds, and not enzymes like DNA gyrase or RNA polymerase.