RNA ligase structures reveal the basis for RNA specificity and conformational changes that drive ligation forward
RNA ligase structures reveal the basis for RNA specificity and conformational changes that drive ligation forward
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DOI：
10.1016/j.cell.2006.08.038
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发表时间：
2006-10-06
期刊：
影响因子：
64.5
通讯作者：
Lima, Christopher D.
中科院分区：
文献类型：
--
作者：
Nandakumar, Jayakrishnan;Shuman, Stewart;Lima, Christopher D.
T4 RNA连接酶2(Rn12)和动态体RNA编辑连接酶是一类RNA修复酶，它们通过连接酶的腺化作用(步骤1)封闭双链RNA中的3‘OH/5’PO4缺口(步骤1)，将AMP转移到Nick 5‘PO4(步骤2)，并由Nick 3’OH攻击5‘-腺基化的链以形成磷酸二酯(步骤3)。Rnl2的晶体结构是沿着这个途径在离散的步骤中被报道的：共价的Rnl2-AMP中间体；Rnl2结合到腺化的镍双链上，在步骤2之后立即捕获；以及Rnl2在腺化的缺口上，处于准备好的步骤3的状态。这些结构阐明了核苷酸转移的立体化学，并揭示了活性部位接触的重塑和构象变化如何推动连接反应的进行。Rnl2和人DNA连接酶尼克结合结构的突变分析和比较我强调了底物识别的共同和不同主题，这可以解释它们在RNA和DNA修复方面的特殊性。
T4 RNA ligase 2 (Rnl2) and kinetoplastid RNA editing ligases exemplify a family of RNA repair enzymes that seal 3'OH/5'PO4 nicks in duplex RNAs via ligase adenylylation (step 1), AMP transfer to the nick 5'PO4 (step 2), and attack by the nick 3'OH on the 5'-adenylylated strand to form a phosphodiester (step 3). Crystal structures are reported for Rnl2 at discrete steps along this pathway: the covalent Rnl2-AMP intermediate; Rnl2 bound to an adenylylated nicked duplex, captured immediately following step 2; and Rnl2 at an adenylylated nick in a state poised for step 3. These structures illuminate the stereochemistry of nucleotidyl transfer and reveal how remodeling of active-site contacts and conformational changes propel the ligation reaction forward. Mutational analysis and comparison of nick-bound structures of Rnl2 and human DNA ligase I highlight common and divergent themes of substrate recognition that can explain their specialization for RNA versus DNA repair.