Non-classical transpeptidases yield insight into new antibacterials.

Bacterial survival requires an intact peptidoglycan layer, a three-dimensional exoskeleton that encapsulates the cytoplasmic membrane. Historically, the final steps of peptidoglycan synthesis are known to be carried out by D,D-transpeptidases, enzymes that are inhibited by the β-lactams, which constitute >50% of all antibacterials in clinical use. Here, we show that the carbapenem subclass of β-lactams are distinctly effective not only because they inhibit D,D-transpeptidases and are poor substrates for β-lactamases, but primarily because they also inhibit non-classical transpeptidases, namely the L,D-transpeptidases, which generate the majority of linkages in the peptidoglycan of mycobacteria. We have characterized the molecular mechanisms responsible for inhibition of L,D-transpeptidases of Mycobacterium tuberculosis and a range of bacteria including ESKAPE pathogens, and used this information to design, synthesize and test simplified carbapenems with potent antibacterial activity.

Citation

Pankaj Kumar, Amit Kaushik, Evan P Lloyd, Shao-Gang Li, Rohini Mattoo, Nicole C Ammerman, Drew T Bell, Alexander L Perryman, Trevor A Zandi, Sean Ekins, Stephan L Ginell, Craig A Townsend, Joel S Freundlich, Gyanu Lamichhane. Non-classical transpeptidases yield insight into new antibacterials. Nature chemical biology. 2017 Jan;13(1):54-61

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PMID: 27820797

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