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Structural highlights

Function

MDFA_ECOLI Efflux pump driven by the proton motive force. Confers resistance to a broad spectrum of chemically unrelated drugs. Confers resistance to a diverse group of cationic or zwitterionic lipophilic compounds such as ethidium bromide, tetraphenylphosphonium, rhodamine, daunomycin, benzalkonium, rifampicin, tetracycline, puromycin, and to chemically unrelated, clinically important antibiotics such as chloramphenicol, erythromycin, and certain aminoglycosides and fluoroquinolones. Overexpression results in isopropyl-beta-D-thiogalactopyranoside (IPTG) exclusion and spectinomycin sensitivity. Transport of neutral substrates is electrogenic, whereas transport of cationic substrates is electroneutral. In addition to its role in multidrug resistance, confers extreme alkaline pH resistance, allowing the growth under conditions that are close to those used normally by alkaliphiles. This activity requires Na(+) or K(+).^{[1] [2] [3] [4] [5]}

References

1. ↑ Lewinson O, Adler J, Poelarends GJ, Mazurkiewicz P, Driessen AJ, Bibi E. The Escherichia coli multidrug transporter MdfA catalyzes both electrogenic and electroneutral transport reactions. Proc Natl Acad Sci U S A. 2003 Feb 18;100(4):1667-72. Epub 2003 Feb 10. PMID:12578981 doi:http://dx.doi.org/10.1073/pnas.0435544100
2. ↑ Lewinson O, Padan E, Bibi E. Alkalitolerance: a biological function for a multidrug transporter in pH homeostasis. Proc Natl Acad Sci U S A. 2004 Sep 28;101(39):14073-8. Epub 2004 Sep 15. PMID:15371593 doi:http://dx.doi.org/10.1073/pnas.0405375101
3. ↑ Edgar R, Bibi E. MdfA, an Escherichia coli multidrug resistance protein with an extraordinarily broad spectrum of drug recognition. J Bacteriol. 1997 Apr;179(7):2274-80. PMID:9079913
4. ↑ Mine T, Morita Y, Kataoka A, Mizushima T, Tsuchiya T. Evidence for chloramphenicol/H+ antiport in Cmr (MdfA) system of Escherichia coli and properties of the antiporter. J Biochem. 1998 Jul;124(1):187-93. PMID:9644262
5. ↑ Bohn C, Bouloc P. The Escherichia coli cmlA gene encodes the multidrug efflux pump Cmr/MdfA and is responsible for isopropyl-beta-D-thiogalactopyranoside exclusion and spectinomycin sensitivity. J Bacteriol. 1998 Nov;180(22):6072-5. PMID:9811673