Biochemical analysis of pistol self-cleaving ribozymes.
Biochemical analysis of pistol self-cleaving ribozymes.
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DOI：
10.1261/rna.052514.115
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发表时间：
2015-11
期刊：
影响因子：
--
通讯作者：
Breaker RR
中科院分区：
文献类型：
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作者：
Harris KA;Lünse CE;Li S;Brewer KI;Breaker RR
Pistol RNA是最近通过生物信息学搜索策略发现的一种独特的自切割核酶的成员。数百个手枪核酶共享一个共同的序列，包括10个高度保守的核苷酸和许多其他与特定二级结构特征相关的适度保守的核苷酸，包括三个碱基配对的茎和一个假结。球形溶杆菌的一种具有代表性的手枪核酶在生理镁离子和pH条件下能促进核糖核酸链断裂，其速率常数为∼10min−1。该反应通过2‘-氧原子对邻近磷中心的亲核攻击进行，因此遵循与迄今发现的所有其他类型的天然自裂解核酶相同的内部磷酸酯转移的一般催化机制。对切割反应的动力学特征和金属离子需求的分析表明，这类核酶的成员可能使用多种催化策略来促进RNA的快速切割。
Pistol RNAs are members of a distinct class of self-cleaving ribozymes that was recently discovered by using a bioinformatics search strategy. Several hundred pistol ribozymes share a consensus sequence including 10 highly conserved nucleotides and many other modestly conserved nucleotides associated with specific secondary structure features, including three base-paired stems and a pseudoknot. A representative pistol ribozyme from the bacterium Lysinibacillus sphaericus was found to promote RNA strand scission with a rate constant of ∼10 min−1 under physiological Mg2+ and pH conditions. The reaction proceeds via the nucleophilic attack of a 2′-oxygen atom on the adjacent phosphorus center, and thus adheres to the same general catalytic mechanism of internal phosphoester transfer as found with all other classes of natural self-cleaving ribozymes discovered to date. Analyses of the kinetic characteristics and the metal ion requirements of the cleavage reaction reveal that members of this ribozyme class likely use several catalytic strategies to promote the rapid cleavage of RNA.