YidC Insertase of Escherichia coli: Water Accessibility and Membrane Shaping
YidC Insertase of Escherichia coli: Water Accessibility and Membrane Shaping
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DOI：
10.1016/j.str.2017.07.008
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发表时间：
2017-09-05
期刊：
影响因子：
5.7
通讯作者：
Dalbey, Ross E.
中科院分区：
文献类型：
--
作者：
Chen, Yuanyuan;Capponi, Sara;Dalbey, Ross E.
YidC/Oxa1/Alb3 膜蛋白家族的功能是将蛋白质插入细菌、线粒体和叶绿体的膜中。最近来自盐芽孢杆菌和大肠杆菌的 YidC 的 X 射线结构揭示了可从脂质双层和细胞质进入的亲水凹槽。在这里，我们利用 POPE/POPG 膜中 YidC 的体内半胱氨酸烷基化扫描和分子动力学 (MD) 模拟来探索大肠杆菌 YidC 保守核心区域内的水可及性。正如结构所预期的那样，YidC 具有位于膜内叶的水膜腔。扫描数据和 MD 模拟均表明，脂质暴露的跨膜螺旋 3、4 和 5 很短，导致 YidC 周围的膜变薄。对 MD 数据的仔细检查揭示了以前未被识别的结构特征，这些特征可能对蛋白质稳定性和功能很重要。
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.