The three-dimensional architecture of the class I ligase ribozyme
The three-dimensional architecture of the class I ligase ribozyme
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DOI：
10.1261/rna.5177504
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发表时间：
2004-02-01
期刊：
影响因子：
4.5
通讯作者：
Bartel, DP
中科院分区：
文献类型：
--
作者：
Bergman, NH;Lau, NC;Bartel, DP
I类连接酶核酶催化Mg++依赖性RNA连接反应，其在化学上类似于RNA聚合的单个步骤。实际上，这种核酶构成了精确的和通用的RNA聚合酶核酶的催化结构域。连接反应在单次和多次周转情况下也非常迅速，因此对于RNA催化以及RNA自我复制的研究是有用的。在这里，我们报告的三维结构的连接酶的初步表征。当连接酶折叠时，几个片段被保护免受羟基自由基切割，这表明RNA采用了紧凑的三级结构。核酶折叠在很大程度上（尽管不是完全）依赖于Mg++，K-1/2[Mg] < 1 mM，并且在宽的温度范围（20 ℃-50 ℃）内观察到。羟基自由基映射，连同比较序列分析和类比的区域内的23 S核糖体RNA，被用来生成一个三维模型的核酶。该模型的预测值进行了测试和支持的光交联实验。
The class I ligase ribozyme catalyzes a Mg++-dependent RNA-ligation reaction that is chemically analogous to a single step of RNA polymerization. indeed, this ribozyme constitutes the catalytic domain of an accurate and general RNA polymerase ribozyme. The ligation reaction is also very rapid in both single- and multiple-turnover contexts and thus is informative for the study of RNA catalysis as well as RNA self-replication. Here we report the initial characterization of the three-dimensional architecture of the ligase. When the ligase folds, several segments become protected from hydroxyl-radical cleavage, indicating that the RNA adopts a compact tertiary structure. Ribozyme folding was largely, though not completely, Mg++ dependent, with a K-1/2[Mg] < 1 mM, and was observed over a broad temperature range (20degreesC-50degreesC). The hydroxyl-radical mapping, together with comparative sequence analyses and analogy to a region within 23S ribosomal RNA, were used to generate a three-dimensional model of the ribozyme. The predictive value of the model was tested and supported by a photo-cross-linking experiment.