Identification of the Asparagine Synthase Responsible for d -Asp Amidation in the Lactococcus lactis Peptidoglycan Interpeptide Crossbridge

Abstract

We show that in Lactococcus lactis , the gene asnH encodes the asparagine synthase involved in amidation of d -Asp present in peptidoglycan side chains and crossbridges. The level of d -Asp amidation in peptidoglycan has a strong effect on the sensitivity of bacteria to endogenous autolysins and to the cationic antimicrobials nisin and lysozyme.