人信号识别颗粒（SRP）RNA中SRP19结合结构域的溶液结构

Solution structure of a SRP19 binding domain in human SRP RNA.

作者信息

Sakamoto Taiichi, Morita Satoshi, Tabata Kazutoshi, Nakamura Kouji, Kawai Gota

机构信息

Department of Industrial Chemistry, Faculty of Engineering, Chiba Institute of Technology, Narashino, Chiba 275-0016, Japan.

出版信息

J Biochem. 2002 Aug;132(2):177-82. doi: 10.1093/oxfordjournals.jbchem.a003207.

DOI:10.1093/oxfordjournals.jbchem.a003207

PMID:12153712

Abstract

Assembly of the human signal recognition particle (SRP) requires SRP19 protein to bind to helices 6 and 8 of SRP RNA. In the present study, structure of a 29-mer RNA composing the SRP19 binding site in helix 6 was determined by NMR spectroscopy. The two A:C mismatches were continuously stacked to each other and formed wobble type A:C base pairs. The GGAG tetraloop in helix 6 was found to adopt a similar conformation to that of GNRA tetraloop, suggesting that these tetraloops are included in an extensive new motif GNRR. Compared with the crystal structure of helix 6 in complex with SRP19 determined previously, the GGAG tetraloop in the complex was found to adopt a similar conformation to the free form, although the loop structure becomes more open upon SRP19 binding. Thus, SRP19 is thought to recognize the overall fold of the GGAG loop.

摘要

人类信号识别颗粒（SRP）的组装需要SRP19蛋白与SRP RNA的螺旋6和螺旋8结合。在本研究中，通过核磁共振光谱法确定了构成螺旋6中SRP19结合位点的29聚体RNA的结构。两个A:C错配彼此连续堆积，形成摆动型A:C碱基对。发现螺旋6中的GGAG四环与GNRA四环具有相似的构象，这表明这些四环包含在一个广泛的新基序GNRR中。与先前确定的与SRP19复合的螺旋6的晶体结构相比，发现复合物中的GGAG四环与游离形式具有相似的构象，尽管在SRP19结合后环结构变得更加开放。因此，认为SRP19识别GGAG环的整体折叠。