High-resolution architecture of the outer membrane of the Gram-negative bacteria Roseobacter denitrificans
High-resolution architecture of the outer membrane of the Gram-negative bacteria Roseobacter denitrificans
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DOI：
10.1111/j.1365-2958.2009.06926.x
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发表时间：
2009-12-01
影响因子：
3.6
通讯作者：
Scheuring, Simon
中科院分区：
文献类型：
--
作者：
Jaroslawski, Szymon;Duquesne, Katia;Scheuring, Simon
革兰氏阴性细菌的外膜保护细胞免受杀菌物质的侵害。营养物质和废物的通过是由外膜孔道和β-桶跨膜通道保证的。虽然已经解决了几个孔蛋白的原子结构，但到目前为止，人们对外膜的超分子结构知之甚少。在这里，我们提出了第一张细菌外膜的高分辨率图，温和地提纯了保留在胞质周壁上的肽聚糖残留物。原子力显微镜显示，外膜碎片的大小相当于细菌包膜的50%，显示外膜孔道的密度比之前假设的要高得多。事实上，外膜是分子筛而不是膜。孔蛋白覆盖约70%的膜表面，形成局部规则的晶格。讨论了暴露的芳香族残基在形成超分子组装中的潜在作用。最后，我们给出了海洋革兰氏阴性细菌反硝化杆菌外膜孔蛋白的第一个结构数据，并与已知结构的孔蛋白进行了序列比对。
P>The outer membrane of Gram-negative bacteria protects the cell against bactericidal substances. Passage of nutrients and waste is assured by outer membrane porins, beta-barrel transmembrane channels. While atomic structures of several porins have been solved, so far little is known on the supramolecular structure of the outer membrane. Here we present the first high-resolution view of a bacterial outer membrane gently purified maintaining remnants of peptidoglycan on the perisplasmic surface. Atomic force microscope images of outer membrane fragments of the size of similar to 50% of the bacterial envelope revealed that outer membrane porins are by far more densely packed than previously assumed. Indeed the outer membrane is a molecular sieve rather than a membrane. Porins cover similar to 70% of the membrane surface and form locally regular lattices. The potential role of exposed aromatic residues in the formation of the supramolecular assembly is discussed. Finally, we present first structural data of the outer membrane porin from the marine Gram-negative bacteria Roseobacter denitrificans, and we perform a sequence alignment with porins of known structure.