title: Identification of a multidrug efflux pump in Mycobacterium smegmatis.
abstract: Cell wall impermeability and active efflux of drugs are among the primary reasons for drug resistance in mycobacteria. Efflux pumps are tripartite membrane localized transport proteins that expel drug molecules outside the cells. Several of such efflux pumps are annotated in mycobacteria, but few have been characterized, like MSMEG_2991, a putative efflux pump permease of Mycobacterium smegmatis To substantiate this, we overexpressed MSMEG_2991 protein in Escherichia coli 2443. Expression of MSMEG_2991 elevated the resistance towards structurally unrelated groups of antibiotics. An active antibiotic efflux pump nature of MSMEG_2991 was revealed by assessing the acquisition of ciprofloxacin in the absence and presence of the efflux pump inhibitor, carbonyl cyanide m-chlorophenyl hydrazone, indicating the involvement of proton-motive force (pmf) during the efflux activity. MSMEG_2991 expression elevated biofilm formation in E. coli by 4-fold, keeping parity to some of the earlier reported efflux pumps. In silico analysis suggested the presence of 12 transmembrane helices in MSMEG_2991 resembling EmrD efflux pump of E. coli Based on in vivo and in silico analyses, MSMEG_2991 may be designated as a pmf-mediated multidrug efflux pump protein that expels diverse groups of antibiotics and might as well be involved in the biofilm enhancement.
authors.affiliation: Department of Biotechnology, Indian Institute of Technology, Kharagpur, West Bengal 721302, India.
authors.forename: Ankita
authors.initials: A
authors.lastname: Bansal
authors.affiliation: Department of Biotechnology, Indian Institute of Technology, Kharagpur, West Bengal 721302, India.
authors.forename: Dhriti
authors.initials: D
authors.lastname: Mallik
authors.affiliation: Department of Biotechnology, Indian Institute of Technology, Kharagpur, West Bengal 721302, India.
authors.forename: Debasish
authors.initials: D
authors.lastname: Kar
authors.affiliation: Department of Biotechnology, Indian Institute of Technology, Kharagpur, West Bengal 721302, India anindyain@yahoo.com.
authors.forename: Anindya S
authors.initials: AS
authors.lastname: Ghosh
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D018441:Biofilms / Q000254:growth & development; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D003198:Computer Simulation; D024901:Drug Resistance, Multiple, Bacterial; D004926:Escherichia coli / Q000235:genetics / Q000502:physiology; D029968:Escherichia coli Proteins / Q000235:genetics; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification*; D008826:Microbial Sensitivity Tests; D020102:Mycobacterium smegmatis / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D018892:Proton-Motive Force
chemical_list: D000900:Anti-Bacterial Agents; C510268:EmrD protein, E coli; D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D002939:Ciprofloxacin
keywords: antibiotic resistance; efflux pump; fluoroquinolones; multidrug; mycobacteria