Characterization of the mycobacterial MSMEG-3762/63 efflux pump in Mycobacterium smegmatis drug efflux

De Siena, Barbara, Campolattano, Nicoletta, D'Abrosca, Gianluca, Russo, Luigi, Cantillon, Daire, Morasco, Rosangela, Muscariello, Lidia, Waddell, Simon J and Sacco, Margherita (2020) Characterization of the mycobacterial MSMEG-3762/63 efflux pump in Mycobacterium smegmatis drug efflux. Frontiers in Microbiology, 11. a575828 1-11. ISSN 1664-302X

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Abstract

Multi-drug resistant tuberculosis (MDR-TB) represents a major health problem worldwide. Drug efflux and the activity of efflux transporters likely play important roles in the development of drug-tolerant and drug-resistant mycobacterial phenotypes. This study is focused on the action of a mycobacterial efflux pump as a mechanism of drug resistance. Previous studies demonstrated up-regulation of the TetR-like transcriptional regulator MSMEG_3765 in Mycobacterium smegmatis and its ortholog Rv1685c in Mycobacterium tuberculosis (Mtb) in acid-nitrosative stress conditions. MSMEG-3765 regulates the expression of the MSMEG_3762/63/65 operon, and of the orthologous region in Mtb (Rv1687c/86c/85c). MSMEG-3762 and Rv1687c are annotated as ATP-binding proteins, while MSMEG-3763 and Rv1686c are annotated as trans-membrane polypeptides, defining an ABC efflux pump in both M. smegmatis and Mtb. The two putative efflux systems share a high percentage of identity. To examine the role of the putative efflux system MSMEG-3762/63, we constructed and characterized a MSMEG-3763 deletion mutant in M. smegmatis (∆MSMEG_3763). By comparative analysis of wild type, knockout, and complemented strains, together with structural modeling and molecular docking bioinformatics analyses of the MSMEG-3763 trans-membrane protein, we define the protein complex MSMEG-3762/63 as an efflux pump. Moreover, we demonstrate involvement of this pump in biofilm development and in the extrusion of rifampicin and ciprofloxacin (CIP), antimicrobial drugs used in first- and second-line anti-TB therapies.

Item Type: Article
Schools and Departments: Brighton and Sussex Medical School > Global Health and Infection
SWORD Depositor: Mx Elements Account
Depositing User: Mx Elements Account
Date Deposited: 02 Dec 2020 08:10
Last Modified: 11 Jan 2021 16:00
URI: http://sro.sussex.ac.uk/id/eprint/95437

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