4zow
From Proteopedia
Crystal structure of E. coli multidrug transporter MdfA in complex with chloramphenicol
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] Publication Abstract from PubMedMultidrug resistance is a serious threat to public health. Proton motive force-driven antiporters from the major facilitator superfamily (MFS) constitute a major group of multidrug-resistance transporters. Currently, no reports on crystal structures of MFS antiporters in complex with their substrates exist. The E. coli MdfA transporter is a well-studied model system for biochemical analyses of multidrug-resistance MFS antiporters. Here, we report three crystal structures of MdfA-ligand complexes at resolutions up to 2.0 A, all in the inward-facing conformation. The substrate-binding site sits proximal to the conserved acidic residue, D34. Our mutagenesis studies support the structural observations of the substrate-binding mode and the notion that D34 responds to substrate binding by adjusting its protonation status. Taken together, our data unveil the substrate-binding mode of MFS antiporters and suggest a mechanism of transport via this group of transporters.Cell Research advance online publication 4 August 2015; doi:10.1038/cr.2015.94. Substrate-bound structure of the E. coli multidrug resistance transporter MdfA.,Heng J, Zhao Y, Liu M, Liu Y, Fan J, Wang X, Zhao Y, Zhang XC Cell Res. 2015 Aug 4. doi: 10.1038/cr.2015.94. PMID:26238402[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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Categories: Ecoli | Large Structures | Heng, J | Wang, X | Zhang, X C | Zhao, Y | Cm | Mdfa | Mfs family | Multi-drug antiporter | Transport protein
