under the action of the VanA ligase (VanA), forms D-alanyl-D-lactate. This becomes the new precursor and is incorporated into
peptidioglycan. Unlike D-alanyl-D-alanine, D-alanyl-D-lactate does not readily bind vancomycin and thus provides resistance to it. The D-lactate
is lost in transpeptidation so the final composition of the peptidoglycan is the same. The vanA operon also encodes a D,D-carboxypeptidase,