Characterization of the annular lipid shell of the Sec translocon
Characterization of the annular lipid shell of the Sec translocon
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DOI：
10.1016/j.bbamem.2015.06.024
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发表时间：
2015-10-01
影响因子：
3.4
通讯作者：
Driessen, Arnold J. M.
中科院分区：
文献类型：
--
作者：
Prabudiansyah, Irfan;Kusters, Ilja;Driessen, Arnold J. M.
细菌 Sec 易位酶的最小形式由膜嵌入的蛋白传导孔 SecYEG 组成，它与运动蛋白 SecA 相互作用，介导分泌蛋白的易位。此外，SecYEG 易位子与附属的 SecDFyajC 膜复合物和膜蛋白插入酶 YidC 相互作用。为了检查 SecYEG 复合物附近的天然脂质环境的组成及其对易位活性的影响，使用苯乙烯-马来酸脂质颗粒 (SMALP) 直接从天然大肠杆菌膜中提取 SecYEG 及其脂质环境，无需使用洗涤剂。这允许与 SecA 复合地共提取 SecYEG，但不能与 SecDFyajC 或 YidC 共提取。 SecYEG-SMALP 的脂质分析揭示了 SecYEG 附近带负电荷的脂质富集，这在去污剂辅助的 Sec 易位酶重建中对于易位活性至关重要。单独提取的 SecDFyajC 或 YidC 没有发现这种脂质富集，这表明 SecYEG 和带负电荷的脂质之间存在特定的相互作用。 (C) 2015 Elsevier B.V. 保留所有权利。
The bacterial Sec translocase in its minimal form consists of a membrane-embedded protein-conducting pore SecYEG that interacts with the motor protein SecA to mediate the translocation of secretory proteins. In addition, the SecYEG translocon interacts with the accessory SecDFyajC membrane complex and the membrane protein insertase YidC. To examine the composition of the native lipid environment in the vicinity of the SecYEG complex and its impact on translocation activity, styrene-maleic acid lipid particles (SMALPs) were used to extract SecYEG with its lipid environment directly from native Escherichia coli membranes without the use of detergents. This allowed the co-extraction of SecYEG in complex with SecA, but not with SecDFyajC or YidC. Lipid analysis of the SecYEG-SMALPs revealed an enrichment of negatively charged lipids in the vicinity of SecYEG, which in detergent assisted reconstitution of the Sec translocase are crucial for the translocation activity. Such lipid enrichment was not found with separately extracted SecDFyajC or YidC, which demonstrates a specific interaction between SecYEG and negatively charged lipids. (C) 2015 Elsevier B.V. All rights reserved.