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Structure. 2017 Sep 5;25(9):1403-1414.e3. doi: 10.1016/j.str.2017.07.008. Epub 2017 Aug 24.

YidC Insertase of Escherichia coli: Water Accessibility and Membrane Shaping.

Author information

1
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
2
Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA.
3
Department of Chemistry, University of California, Irvine, CA 92697, USA.
4
Department of Physiology and Biophysics, University of California, Irvine, CA 92697, USA. Electronic address: stephen.white@uci.edu.
5
Department of Chemistry and Biochemistry, The Ohio State University, Columbus, OH 43210, USA. Electronic address: dalbey@chemistry.ohio-state.edu.

Abstract

The YidC/Oxa1/Alb3 family of membrane proteins function to insert proteins into membranes in bacteria, mitochondria, and chloroplasts. Recent X-ray structures of YidC from Bacillus halodurans and Escherichia coli revealed a hydrophilic groove that is accessible from the lipid bilayer and the cytoplasm. Here, we explore the water accessibility within the conserved core region of the E. coli YidC using in vivo cysteine alkylation scanning and molecular dynamics (MD) simulations of YidC in POPE/POPG membranes. As expected from the structure, YidC possesses an aqueous membrane cavity localized to the membrane inner leaflet. Both the scanning data and the MD simulations show that the lipid-exposed transmembrane helices 3, 4, and 5 are short, leading to membrane thinning around YidC. Close examination of the MD data reveals previously unrecognized structural features that are likely important for protein stability and function.

KEYWORDS:

YidC; alkylation; aqueous access; cysteine-scanning mutagenesis; membrane protein folding; membrane protein insertion; membrane thinning; molecular dynamics

PMID:
28844594
PMCID:
PMC5675557
DOI:
10.1016/j.str.2017.07.008
[Indexed for MEDLINE]
Free PMC Article

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