
Abstract
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.
Item Type: | Journal article |
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Faculties: | Chemistry and Pharmacy > Department of Biochemistry |
Subjects: | 500 Science > 540 Chemistry |
URN: | urn:nbn:de:bvb:19-epub-37392-2 |
ISSN: | 2211-1247 |
Language: | English |
Item ID: | 37392 |
Date Deposited: | 04. May 2017, 13:09 |
Last Modified: | 04. Nov 2020, 14:43 |