SRP RNA Remodeling by SRP68 Explains Its Role in Protein Translocation
SRP RNA Remodeling by SRP68 Explains Its Role in Protein Translocation
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DOI：
10.1126/science.1249094
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发表时间：
2014-04-04
期刊：
影响因子：
56.9
通讯作者：
Sinning, Irmgard
中科院分区：
文献类型：
--
作者：
Grotwinkel, Jan Timo;Wild, Klemens;Sinning, Irmgard
信号识别颗粒（SRP）是膜蛋白靶向的核心; SRP RNA对于SRP组装、延伸停滞和SRP鸟苷三磷酸酶的活化是必不可少的。在真核生物中，SRP功能依赖于SRP 68-SRP 72异二聚体。我们目前的晶体结构的RNA结合结构域的SRP 68（SRP 68-RBD）单独和复杂的SRP RNA和SRP 19。SRP 68-RBD是一种三肽样模块，其与RNA三向连接点结合，使RNA弯曲，并将α-螺旋富含丝氨酸基序（ARM）插入大沟中。ARM打开保守的5 f RNA环，其在核糖体结合的SRP中建立与核糖体RNA的接触。我们的数据提供了真核生物特异性的结构基础，SRP 68驱动的RNA重塑所需的蛋白质易位。
The signal recognition particle (SRP) is central to membrane protein targeting; SRP RNA is essential for SRP assembly, elongation arrest, and activation of SRP guanosine triphosphatases. In eukaryotes, SRP function relies on the SRP68-SRP72 heterodimer. We present the crystal structures of the RNA-binding domain of SRP68 (SRP68-RBD) alone and in complex with SRP RNA and SRP19. SRP68-RBD is a tetratricopeptide-like module that binds to a RNA three-way junction, bends the RNA, and inserts an alpha-helical arginine-rich motif (ARM) into the major groove. The ARM opens the conserved 5f RNA loop, which in ribosome-bound SRP establishes a contact to ribosomal RNA. Our data provide the structural basis for eukaryote-specific, SRP68-driven RNA remodeling required for protein translocation.