D-Alanyl-d-Alanine Ligase as a Broad-Host-Range Counterselection Marker in Vancomycin-Resistant Lactic Acid Bacteria.

ABSTRACT: The peptidoglycan composition in lactic acid bacteria dictates vancomycin resistance. Vancomycin binds relatively poorly to peptidoglycan ending in d-alanyl-d-lactate and binds with high affinity to peptidoglycan ending in d-alanyl-d-alanine (d-Ala-d-Ala), which results in vancomycin resistance and sensitivity, respectively. The enzyme responsible for generating these peptidoglycan precursors is dipeptide ligase (Ddl). A single amino acid in the Ddl active site, phenylalanine or tyrosine, determines depsipeptide or dipeptide activity, respectively. Here, we established that heterologous expression of dipeptide ligase in vancomycin-resistant lactobacilli increases their sensitivity to vancomycin in a dose-dependent manner and overcomes the effects of the presence of a native d-Ala-d-Ala dip

SUBMITTER: Zhang S 

PROVIDER: S-EPMC5996685 | biostudies-literature | 2018 Jul

REPOSITORIES: biostudies-literature