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Updated: Jun 6, 2026

Transmembrane Domain Oligomerization Propensity determined by ToxR Assay
Published on: May 26, 2011
The oligomeric state and arrangement of the active bacterial translocon
Karine Deville1, Vicki A M Gold, Alice Robson
1Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom.
Abstract:
Protein secretion in bacteria is driven through the ubiquitous SecYEG complex by the ATPase SecA. The structure of SecYEG alone or as a complex with SecA in detergent reveal a monomeric heterotrimer enclosing a central protein channel, yet in membranes it is dimeric. We have addressed the functional significance of the oligomeric status of SecYEG in protein translocation using single molecule and ensemble methods. The results show that while monomers are sufficient for the SecA- and ATP-dependent association of SecYEG with pre-protein, active transport requires SecYEG dimers arranged in the back-to-back conformation. Molecular modeling of this dimeric structure, in conjunction with the new functional data, provides a rationale for the presence of both active and passive copies of SecYEG in the functional translocon.
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