Vancomycin antibiotic action. Computer model showing the secondary structure of the enzyme glycosyltransferase (spirals and ribbons). Bound to the enzyme are thymidine 5' diphosphate (spheres, left) and the antibiotic vancomycin (spheres, right). Glycosyltransferase is involved in synthesising bacterial cell walls. Thymidine 5' diphosphate is a component of some bacterial cell walls. Vancomycin works by inhibiting the synthesis of Gram positive bacterial cell walls. It binds to glycosyltransferase and inhibits its function.