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The projection structure of EmrE, a proton-linked multidrug transporter from Escherichia coli, at 7 Å resolution
被引:95
作者:
Tate, CG
Kunji, ERS
Lebendiker, M
Schuldiner, S
机构:
[1] MRC, Mol Biol Lab, Cambridge CB2 2QH, England
[2] MRC, Dunn Human Nutr Unit, Cambridge CB2 2XY, England
[3] Hebrew Univ Jerusalem, Inst Life Sci, IL-91904 Jerusalem, Israel
关键词:
ion-coupled transport;
membrane proteins;
multidrug resistance;
structure;
D O I:
10.1093/emboj/20.1.77
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
EmrE belongs to a family of eubacterial multidrug transporters that confer resistance to a wide variety of toxins by coupling the influx of protons to toxin extrusion. EmrE was purified and crystallized in two dimensions by reconstitution with dimyristoylphosphatidylcholine into lipid bilayers, Images of frozen hydrated crystals were collected by cryo-electron microscopy and a projection structure of EmrE was calculated to 7 Angstrom resolution. The projection map shows an asymmetric EmrE dimer with overall dimensions similar to 31 x 40 Angstrom, comprising an are of highly tilted helices separating two helices nearly perpendicular to the membrane from another two helices, one tilted and the other nearly perpendicular. There is no obvious 2-fold symmetry axis perpendicular to the membrane within the dimer, suggesting that the monomers may have different structures in the functional unit.
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页码:77 / 81
页数:5
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