Crystal structure of the conserved subdomain of human protein SRP54M at 2.1 Å resolution:: Evidence for the mechanism of signal peptide binding
Crystal structure of the conserved subdomain of human protein SRP54M at 2.1 Å resolution:: Evidence for the mechanism of signal peptide binding
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DOI：
10.1006/jmbi.1999.3090
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发表时间：
1999-09-24
影响因子：
5.6
通讯作者：
Ramakrishnan, V
中科院分区：
文献类型：
--
作者：
Clemons, WM;Gowda, K;Ramakrishnan, V
蛋白质SRP 54是哺乳动物信号识别颗粒（SRP）的组成部分，SRP是一种胞质核糖核蛋白复合物，其与核糖体缔合并用于识别、结合和转运预定用于膜或分泌的蛋白质。当新生蛋白从核糖体中出现时，蛋白SRP 54的富含甲硫氨酸的M结构域（SRP 54 M）结合SRP RNA和信号肽。这一关键的细胞功能的焦点是详细了解不同的疏水性信号肽是如何有效地识别和具体运输，尽管在序列上有相当大的变化。我们已经在2.1埃分辨率下解析了人SRP 54蛋白（hSRP 54 m）的保守功能亚结构域的晶体结构，显示了具有大部分可用于结合的结构的主要α螺旋蛋白。预测RNA结合发生在螺旋4至6附近。N-末端螺旋从结构的核心显著延伸到相邻分子的大但狭窄的疏水沟中，从而揭示了α螺旋信号肽与人SRP 54之间可能相互作用的分子细节。(C)北京：科学出版社.
Protein SRP54 is an integral part of the mammalian signal recognition particle (SRP), a cytosolic ribonucleoprotein complex which associates with ribosomes and serves to recognize, bind, and transport proteins destined for the membrane or secretion. The methionine-rich M-domain of protein SRP54 (SRP54M) binds the SRP RNA and the signal peptide as the nascent protein emerges from the ribosome. A focal point of this critical cellular function is the detailed understanding of how different hydrophobic signal peptides are recognized efficiently and transported specifically, despite considerable variation in sequence. We have solved the crystal structure of a conserved functional subdomain of the human SRP54 protein (hSRP54m) at 2.1 Angstrom resolution showing a predominantly alpha helical protein with a large fraction of the structure available for binding. RNA binding is predicted to occur in the vicinity of helices 4 to 6. The N-terminal helix extends significantly from the core of the structure into a large but constricted hydrophobic groove of an adjacent molecule, thus revealing molecular details of possible interactions between alpha helical signal peptides and human SRP54. (C) 1999 Academic Press.