RNA splicing: group I intron crystal structures reveal the basis of splice site selection and metal ion catalysis.
RNA splicing: group I intron crystal structures reveal the basis of splice site selection and metal ion catalysis.
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RNA 剪接：I 族内含子晶体结构揭示了剪接位点选择和金属离子催化的基础。
DOI：
10.1016/j.sbi.2006.04.005
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
Strobel,ScottA
中科院分区：
文献类型：
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作者：
Stahley,MaryR;Strobel,ScottA
I组内含子自25年前被发现以来一直是RNA催化的模型。四个最近确定的高分辨率晶体结构补充了对该系统的广泛的生物化学研究。Azoarcus，四膜虫和噬菌体Twort组I内含子的结构模拟剪接或核酶反应途径的不同状态，并提供剪接位点选择和金属离子催化的信息。5′-剪接位点通过5′-外显子末端和内含子之间形成保守的G·U摆动对来选择。3′-剪接位点是通过三个碱基三联体的堆叠来确定的，其中中间的三联体包含内含子的保守末端核苷酸ΩG。这些结构支持I组内含子剪接的双金属离子机制，其可能与剪接体对II组内含子和前mRNA剪接有必然联系。
The group I intron has served as a model for RNA catalysis since its discovery 25 years ago. Four recently determined high-resolution crystal structures complement extensive biochemical studies on this system. Structures of the Azoarcus, Tetrahymena and bacteriophage Twort group I introns mimic different states of the splicing or ribozyme reaction pathway and provide information on splice site selection and metal ion catalysis. The 5′-splice site is selected by formation of a conserved G·U wobble pair between the 5′-exon terminus and the intron. The 3′-splice site is identified through stacking of three base triples, in which the middle triple contains the conserved terminal nucleotide of the intron, ΩG. The structures support a two-metal-ion mechanism for group I intron splicing that might have corollaries to group II intron and pre-mRNA splicing by the spliceosome.