Gene duplication of the eight-stranded β-barrel OmpX produces a functional pore:: A scenario for the evolution of transmembrane β-barrels
Gene duplication of the eight-stranded β-barrel OmpX produces a functional pore:: A scenario for the evolution of transmembrane β-barrels
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DOI：
10.1016/j.jmb.2006.12.029
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发表时间：
2007-03-02
影响因子：
5.6
通讯作者：
Linke, Dirk
中科院分区：
文献类型：
--
作者：
Arnold, Thomas;Poynor, Melissa;Linke, Dirk
来自革兰氏阴性细菌的外膜β桶的重复单位是β发pin，该蛋白质家族的代表始终在八到22之间均匀的链数。两种主导的结构形式分别具有八个和16链，表明基因复制是其进化的可能机制。我们复制了已知结构的八链β-桶蛋白Ompx的序列，并获得了指定的opp2X的β-桶，该β可以在体外和体内折叠。使用单通道电导测量和PEG排除测定法，我们发现OMP2X的孔径与天然16链的枪管OMPC相似。同源蛋白OMPX，OMPA和OMPW的融合能够在所有测试的组合中在体外折叠，这表明形成β桶的一般倾向足以通过简单的遗传事件来进化更大的桶。 （c）2006 Elsevier Ltd.保留所有权利。
The repeating unit of outer membrane beta-barrels from Gram-negative bacteria is the beta-hairpin, and representatives of this protein family always have an even strand number between eight and 22. Two dominant structural forms have eight and 16 strands, respectively, suggesting gene duplication as a possible mechanism for their evolution. We duplicated the sequence of OmpX, an eight-stranded beta-barrel protein of known structure, and obtained a beta-barrel, designated Omp2X, which can fold in vitro and in vivo. Using single-channel conductance measurements and PEG exclusion assays, we found that Omp2X has a pore size similar to that of OmpC, a natural 16-stranded barrel. Fusions of the homologous proteins OmpX, OmpA and OmpW were able to fold in vitro in all combinations tested, revealing that the general propensity to form a beta-barrel is sufficient to evolve larger barrels by simple genetic events. (c) 2006 Elsevier Ltd. All rights reserved.