A specific monovalent metal ion integral to the AA platform of the RNA tetraloop receptor
A specific monovalent metal ion integral to the AA platform of the RNA tetraloop receptor
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DOI：
10.1038/2960
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发表时间：
1998-11-01
期刊：
影响因子：
--
通讯作者：
Doudna, JA
中科院分区：
文献类型：
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作者：
Basu, S;Rambo, RP;Doudna, JA
金属离子对于大分子催化RNA的折叠和活性是必不可少的。虽然二价金属离子直接参与了RNA三级结构的形成，但单价离子的作用在很大程度上还没有被探索过。在这里，我们报道了催化RNA中第一个特定的单价金属离子结合位点。如结晶学所见，钾离子直接配位在四膜虫核酶P4-P6结构域的AA平台下方，包括四层受体内的平台。干扰和动力学实验表明，与Tetraloop受体结合的钾离子稳定了P4-P6结构域的折叠，并增强了Azoarcus Group I内含子的活性。由于单价离子结合位点是四环受体所必需的，四环受体是RNA中常见的三级结构基序，单价金属离子可能参与多种RNA的折叠和活性。
Metal ions are essential for the folding and activity of large catalytic RNAs. While divalent metal ions have been directly implicated in RNA tertiary structure formation, the role of monovalent ions has been largely unexplored. Here we report the first specific monovalent metal ion binding site within a catalytic RNA. As seen crystallographically, a potassium ion is coordinated immediately below AA platforms of the Tetrahymena ribozyme P4-P6 domain, including that within the tetraloop receptor. Interference and kinetic experiments demonstrate that potassium ion binding within the tetraloop receptor stabilizes the folding of the P4-P6 domain and enhances the activity of the Azoarcus group I intron. Since a monovalent ion binding site is integral to the tetraloop receptor, a tertiary structural motif that occurs frequently in RNA, monovalent metal ions are likely to participate in the folding and activity of a wide diversity of RNAs.