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The projection structure of EmrE, a proton‐linked multidrug transporter from Escherichia coli , at 7 Å resolution
Author(s) -
Tate Christopher G.,
Kunji Edmund R. S.,
Lebendiker Mario,
Schuldiner Shimon
Publication year - 2001
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/20.1.77
Subject(s) - biology , escherichia coli , resolution (logic) , transporter , escherichia coli proteins , projection (relational algebra) , computational biology , microbiology and biotechnology , genetics , gene , algorithm , artificial intelligence , computer science
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 Å resolution. The projection map shows an asymmetric EmrE dimer with overall dimensions ∼31 × 40 Å, comprising an arc 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.