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The conformations and basal conformational dynamics of translocation factor SecDF vary with translocon SecYEG interaction.
Weaver, D R; Amin, D N; King, G M.
Afiliación
  • Weaver DR; Department of Physics and Astronomy, University of Missouri, Columbia, Missouri, USA.
  • Amin DN; Department of Biochemistry, University of Missouri, Columbia, Missouri, USA.
  • King GM; Department of Physics and Astronomy, University of Missouri, Columbia, Missouri, USA; Department of Biochemistry, University of Missouri, Columbia, Missouri, USA. Electronic address: kinggm@missouri.edu.
J Biol Chem ; 298(10): 102412, 2022 10.
Article en En | MEDLINE | ID: mdl-36007614
The general secretory, or Sec, system is a primary protein export pathway from the cytosol of Escherichia coli and all eubacteria. Integral membrane protein complex SecDF is a translocation factor that enhances polypeptide secretion, which is driven by the Sec translocase, consisting of translocon SecYEG and ATPase SecA. SecDF is thought to utilize a proton gradient to effectively pull precursor proteins from the cytoplasm into the periplasm. Working models have been developed to describe the structure and function of SecDF, but important mechanistic questions remain unanswered. Atomic force microscopy (AFM) is a powerful technique for studying the dynamics of single-molecule systems including membrane proteins in near-native conditions. The sharp tip of the AFM provides direct access to membrane-external protein conformations. Here, we acquired AFM images and kymographs (∼100 ms resolution) to visualize SecDF protrusions in near-native supported lipid bilayers and compared the experimental data to simulated AFM images based on static structures. When studied in isolation, SecDF exhibited a stable and compact conformation close to the lipid bilayer surface, indicative of a resting state. Interestingly, upon SecYEG introduction, we observed changes in both SecDF conformation and conformational dynamics. The population of periplasmic protrusions corresponding to an intermediate form of SecDF, which is thought to be active in precursor protein handling, increased more than ninefold. In conjunction, our dynamics measurements revealed an enhancement in the transition rate between distinct SecDF conformations when the translocon was present. Together, this work provides a novel vista of basal-level SecDF conformational dynamics in near-native conditions.
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Proteínas de Escherichia coli / Escherichia coli / Canales de Translocación SEC Tipo de estudio: Prognostic_studies Idioma: En Revista: J Biol Chem Año: 2022 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos
Texto completo
Añadir a Mi BVS
Imprimir
XML
PubMed Links
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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Proteínas de Escherichia coli / Escherichia coli / Canales de Translocación SEC Tipo de estudio: Prognostic_studies Idioma: En Revista: J Biol Chem Año: 2022 Tipo del documento: Article País de afiliación: Estados Unidos Pais de publicación: Estados Unidos