Peptidoglycan Cross-Linking Activity of l,d-Transpeptidases from Clostridium difficile and Inactivation of These Enzymes by β-Lactams.

ABSTRACT: In most bacteria, the essential targets of β-lactam antibiotics are the d,d-transpeptidases that catalyze the last step of peptidoglycan polymerization by forming 4→3 cross-links. The peptidoglycan of Clostridium difficile is unusual since it mainly contains 3→3 cross-links generated by l,d-transpeptidases. To gain insight into the characteristics of C. difficile peptidoglycan cross-linking enzymes, we purified the three putative C. difficile l,d-transpeptidase paralogues LdtCd1, LdtCd2, and LdtCd3, which were previously identified by sequence analysis. The catalytic activities of the three proteins were assayed with a disaccharide-tetrapeptide purified from the C. difficile cell wall. LdtCd2 and LdtCd3 catalyzed the formation of 3→3 cross-links (l,d-transpeptidase activity), the hydrolysi

SUBMITTER: Sutterlin L 

PROVIDER: S-EPMC5740366 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature