title: Dual-topology insertion of a dual-topology membrane protein.
abstract: Some membrane transporters are dual-topology dimers in which the subunits have inverted transmembrane topology. How a cell manages to generate equal populations of two opposite topologies from the same polypeptide chain remains unclear. For the dual-topology transporter EmrE, the evidence to date remains consistent with two extreme models. A post-translational model posits that topology remains malleable after synthesis and becomes fixed once the dimer forms. A second, co-translational model, posits that the protein inserts in both topologies in equal proportions. Here we show that while there is at least some limited topological malleability, the co-translational model likely dominates under normal circumstances.
authors: Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095-1570, USA.
authors: Nicholas B
authors: NB
authors: Woodall
authors: Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095-1570, USA.
authors: Ying
authors: Y
authors: Yin
authors: Department of Chemistry and Biochemistry, UCLA-DOE Institute, Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095-1570, USA.
authors: James U
authors: JU
authors: Bowie
mesh_terms: D049069:ATP-Dependent Proteases / Q000235:genetics; D017920:Antiporters / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D011487:Protein Conformation; D046188:Protein Modification, Translational; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary
chemical_list: D017920:Antiporters; D029968:Escherichia coli Proteins; C075436:EmrE protein, E coli; D049069:ATP-Dependent Proteases; C513383:FtsH protein, E coli