Inter-membrane association of the Sec and BAM translocons for bacterial outer-membrane biogenesis.
Inter-membrane association of the Sec and BAM translocons for bacterial outer-membrane biogenesis.
复制标题
细菌外膜生物发生中Sec和BAM转位子的膜间结合。
DOI：
10.7554/elife.60669
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发表时间：
2020-11-04
期刊：
影响因子：
7.7
通讯作者：
Collinson I
中科院分区：
文献类型：
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作者：
Alvira S;Watkins DW;Troman L;Allen WJ;Lorriman JS;Degliesposti G;Cohen EJ;Beeby M;Daum B;Gold VA;Skehel JM;Collinson I
革兰氏阴性菌的外膜对表面粘附、致病性、抗生素耐药性和存活至关重要。其主要成分疏水β桶外膜蛋白（OMPs）首先通过sec转座子在细胞膜上分泌，传递给质周伴侣，如SurA，以防止聚集。然后将omp卸载到外膜的β-桶组装机械（BAM）中进行插入和折叠。我们展示了Holo-TransLocon （html）——一个由蛋白质通道核心复合物SecYEG、辅助亚复合物SecDF和膜插入酶YidC组成的组装体——通过SecDF和YidC的周质结构域与BAM接触，确保OMP的有效成熟。此外，跨细胞膜的质子动力（PMF）在蛋白质分泌的不同阶段起作用：(1)seca通过SecYEG驱动的易位；(2)通过SecDF通过外周质传递构象变化到BAM。后者可能会推动omp的有效通过。这些相互作用提供了膜间组织和通信的见解，其重要性正变得越来越明显。
The outer-membrane of Gram-negative bacteria is critical for surface adhesion, pathogenicity, antibiotic resistance and survival. The major constituent – hydrophobic β-barrel Outer-Membrane Proteins (OMPs) – are first secreted across the inner-membrane through the Sec-translocon for delivery to periplasmic chaperones, for example SurA, which prevent aggregation. OMPs are then offloaded to the β-Barrel Assembly Machinery (BAM) in the outer-membrane for insertion and folding. We show the Holo-TransLocon (HTL) – an assembly of the protein-channel core-complex SecYEG, the ancillary sub-complex SecDF, and the membrane ‘insertase’ YidC – contacts BAM through periplasmic domains of SecDF and YidC, ensuring efficient OMP maturation. Furthermore, the proton-motive force (PMF) across the inner-membrane acts at distinct stages of protein secretion: (1) SecA-driven translocation through SecYEG and (2) communication of conformational changes via SecDF across the periplasm to BAM. The latter presumably drives efficient passage of OMPs. These interactions provide insights of inter-membrane organisation and communication, the importance of which is becoming increasingly apparent.