Structural Dynamics of the YidC:Ribosome Complex during Membrane Protein Biogenesis.

Members of the YidC/Oxa1/Alb3 family universally facilitate membrane protein biogenesis, via mechanisms that have thus far remained unclear. Here, we investigated two crucial functional aspects: the interaction of YidC with ribosome:nascent chain complexes (RNCs) and the structural dynamics of RNC-bound YidC in nanodiscs. We observed that a fully exposed nascent transmembrane domain (TMD) is required for high-affinity YidC:RNC interactions, while weaker binding may already occur at earlier stages of translation. YidC efficiently catalyzed the membrane insertion of nascent TMDs in both fluid and gel phase membranes. Cryo-electron microscopy and fluorescence analysis revealed a conformational change in YidC upon nascent chain insertion: the essential TMDs 2 and 3 of YidC were tilted, while the amphipathic helix EH1 relocated into the hydrophobic core of the membrane. We suggest that EH1 serves as a mechanical lever, facilitating a coordinated movement of YidC TMDs to trigger the release of nascent chains into the membrane. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Citation

Alexej Kedrov, Stephan Wickles, Alvaro H Crevenna, Eli O van der Sluis, Robert Buschauer, Otto Berninghausen, Don C Lamb, Roland Beckmann. Structural Dynamics of the YidC:Ribosome Complex during Membrane Protein Biogenesis. Cell reports. 2016 Dec 13;17(11):2943-2954

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PMID: 27974208

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