Structural highlights
Function
[EMRE_ECOLI] Multidrug transporter that expels positively charged hydrophobic drugs across the inner membrane of E.coli., thereby conferring resistance to a wide range of toxic compounds. The drug efflux is coupled to an influx of protons. Is involved in the resistance of E.coli cells to methyl viologen, ethidium bromide and acriflavine. Is also able to transport tetraphenylphosphonium (TPP(+)) and benzalkonium.[1] [2] [3]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
EmrE, a multidrug transporter from Escherichia coli, functions as a homodimer of a small four-transmembrane protein. The membrane insertion topology of the two monomers is controversial. Although the EmrE protein was reported to have a unique orientation in the membrane, models based on electron microscopy and now defunct x-ray structures, as well as recent biochemical studies, posit an antiparallel dimer. We have now reanalyzed our x-ray data on EmrE. The corrected structures in complex with a transport substrate are highly similar to the electron microscopy structure. The first three transmembrane helices from each monomer surround the substrate binding chamber, whereas the fourth helices participate only in dimer formation. Selenomethionine markers clearly indicate an antiparallel orientation for the monomers, supporting a "dual topology" model.
X-ray structure of EmrE supports dual topology model.,Chen YJ, Pornillos O, Lieu S, Ma C, Chen AP, Chang G Proc Natl Acad Sci U S A. 2007 Nov 27;104(48):18999-9004. Epub 2007 Nov, 16. PMID:18024586[4]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Yerushalmi H, Lebendiker M, Schuldiner S. EmrE, an Escherichia coli 12-kDa multidrug transporter, exchanges toxic cations and H+ and is soluble in organic solvents. J Biol Chem. 1995 Mar 24;270(12):6856-63. PMID:7896833
- ↑ Yerushalmi H, Schuldiner S. An essential glutamyl residue in EmrE, a multidrug antiporter from Escherichia coli. J Biol Chem. 2000 Feb 25;275(8):5264-9. PMID:10681497
- ↑ Rotem D, Schuldiner S. EmrE, a multidrug transporter from Escherichia coli, transports monovalent and divalent substrates with the same stoichiometry. J Biol Chem. 2004 Nov 19;279(47):48787-93. Epub 2004 Sep 15. PMID:15371426 doi:10.1074/jbc.M408187200
- ↑ Chen YJ, Pornillos O, Lieu S, Ma C, Chen AP, Chang G. X-ray structure of EmrE supports dual topology model. Proc Natl Acad Sci U S A. 2007 Nov 27;104(48):18999-9004. Epub 2007 Nov, 16. PMID:18024586
