Dual-topology insertion of a dual-topology membrane protein.
- Author(s): Woodall, Nicholas B;
- Yin, Ying;
- Bowie, James U
- et al.
Published Web Locationhttps://doi.org/10.1038/ncomms9099
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.