Proton transfer activity of the reconstituted Mycobacterium tuberculosis MmpL3 is modulated by substrate mimics and inhibitors

Casey M. Stevens, Svitlana O. Babii, Amitkumar N. Pandya, Wei Li, Yupeng Li, Jitender Mehla, Robyn Scott, Pooja Hegde, Pavan K. Prathipati, Atanu Acharya, Jinchan Liu, James C. Gumbart, Jeffrey North, Mary Jackson, Helen I. Zgurskaya

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


Transporters belonging to the Resistance-Nodulation-cell Division (RND) superfamily of proteins such as Mycobacterium tuberculosis MmpL3 and its analogs are the focus of intense investigations due to their importance in the physiology of Corynebacterium- Mycobacterium-Nocardia species and antimycobacterial drug discovery. These transporters deliver trehalose monomycolates, the precursors of major lipids of the outer membrane, to the periplasm by a proton motive force-dependent mechanism. In this study, we successfully purified, from native membranes, the full-length and the C-terminal truncated M. tuberculosis MmpL3 and Corynebacterium glutamicum CmpL1 proteins and reconstituted them into proteoliposomes. We also generated a series of substrate mimics and inhibitors specific to these transporters, analyzed their activities in the reconstituted proteoliposomes, and carried out molecular dynamics simulations of the model MmpL3 transporter at different pH. We found that all reconstituted proteins facilitate proton translocation across a phospholipid bilayer, but MmpL3 and CmpL1 differ dramatically in their responses to pH and interactions with substrate mimics and indole-2-carboxamide inhibitors. Our results further suggest that some inhibitors abolish the transport activity of MmpL3 and CmpL1 by inhibition of proton translocation.

Original languageEnglish (US)
Article numbere2113963119
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number30
StatePublished - Jul 26 2022
Externally publishedYes


  • Tuberculosis
  • drug target
  • membrane transporter
  • reconstitution

ASJC Scopus subject areas

  • General


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