Structural model for the protein-translocating element of the twin-arginine transport system
Structural model for the protein-translocating element of the twin-arginine transport system
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DOI：
10.1073/pnas.1219486110
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发表时间：
2013-03-19
影响因子：
11.1
通讯作者：
Schnell, Jason R.
中科院分区：
文献类型：
--
作者：
Rodriguez, Fernanda;Rouse, Sarah L.;Schnell, Jason R.
双精氨酸移位酶（达特）是将完全折叠的蛋白质跨原核生物细胞质膜和植物叶绿体类囊体膜进行移位的重要过程。达特是细菌致病和植物光合作用所必需的。TatA是达特系统的蛋白质转运元件，是一种小的跨膜蛋白，可组装成大小不等的环状寡聚体。我们已经确定了结构模型的大肠杆菌TatA复合物在洗涤剂溶液中的NMR。TatA组装完全由跨膜螺旋介导。两亲性螺旋从跨膜螺旋环向外延伸，允许组装具有可变亚基数目的复合物。跨膜残基Gln8向内指向，导致在复合物中心的短疏水孔。模拟的TatA复合物的脂质双层表明，短的跨膜结构域扭曲的膜。这一发现表明，TatA通过使膜对瞬时破裂敏感来促进蛋白质转运。
The twin-arginine translocase (Tat) carries out the remarkable process of translocating fully folded proteins across the cytoplasmic membrane of prokaryotes and the thylakoid membrane of plant chloroplasts. Tat is required for bacterial pathogenesis and for photosynthesis in plants. TatA, the protein-translocating element of the Tat system, is a small transmembrane protein that assembles into ring-like oligomers of variable size. We have determined a structural model of the Escherichia coli TatA complex in detergent solution by NMR. TatA assembly is mediated entirely by the transmembrane helix. The amphipathic helix extends outwards from the ring of transmembrane helices, permitting assembly of complexes with variable subunit numbers. Transmembrane residue Gln8 points inward, resulting in a short hydrophobic pore in the center of the complex. Simulations of the TatA complex in lipid bilayers indicate that the short transmembrane domain distorts the membrane. This finding suggests that TatA facilitates protein transport by sensitizing the membrane to transient rupture.