RNA连接酶的结构与机制。

Structure and mechanism of RNA ligase.

作者信息

Ho C Kiong, Wang Li Kai, Lima Christopher D, Shuman Stewart

机构信息

Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10021, USA.

出版信息

Structure. 2004 Feb;12(2):327-39. doi: 10.1016/j.str.2004.01.011.

DOI:10.1016/j.str.2004.01.011

PMID:14962393

Abstract

T4 RNA ligase 2 (Rnl2) exemplifies an RNA ligase family that includes the RNA editing ligases (RELs) of Trypanosoma and Leishmania. The Rnl2/REL enzymes are defined by essential signature residues and a unique C-terminal domain, which we show is essential for sealing of 3'-OH and 5'-PO4 RNA ends by Rnl2, but not for ligase adenylation or phosphodiester bond formation at a preadenylated AppRNA end. The N-terminal segment Rnl2(1-249) of the 334 aa Rnl2 protein comprises an autonomous adenylyltransferase/AppRNA ligase domain. We report the 1.9 A crystal structure of the ligase domain with AMP bound at the active site, which reveals a shared fold, catalytic mechanism, and evolutionary history for RNA ligases, DNA ligases, and mRNA capping enzymes.

摘要

T4 RNA连接酶2（Rnl2）是RNA连接酶家族的一个典型例子，该家族包括锥虫和利什曼原虫的RNA编辑连接酶（RELs）。Rnl2/REL酶由必需的特征性残基和一个独特的C末端结构域所定义，我们的研究表明，该结构域对于Rnl2封闭3'-OH和5'-PO4 RNA末端至关重要，但对于连接酶腺苷酸化或在预腺苷酸化的AppRNA末端形成磷酸二酯键则并非必需。334个氨基酸的Rnl2蛋白的N末端片段Rnl2(1-249)包含一个自主的腺苷酸转移酶/AppRNA连接酶结构域。我们报道了连接酶结构域与结合在活性位点的AMP的1.9埃晶体结构，该结构揭示了RNA连接酶、DNA连接酶和mRNA加帽酶的共同折叠、催化机制和进化历史。