Catalytic center of an archaeal type 2 ribonuclease H as revealed by X-ray crystallographic and mutational analyses
Catalytic center of an archaeal type 2 ribonuclease H as revealed by X-ray crystallographic and mutational analyses
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DOI：
10.1110/ps.48001
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发表时间：
2001-04-01
期刊：
影响因子：
8
通讯作者：
Morikawa, K
中科院分区：
文献类型：
--
作者：
Muroya, A;Tsuchiya, D;Morikawa, K
一个古细菌2型核糖核酸酶H的催化中心已经通过X-射线晶体学和突变分析的组合被确定。来自Thermococcus kodakaraensis KOD 1的2型RNA酶H的晶体结构揭示了N-末端主要结构域采用RNA酶H折叠，尽管与1型RNA酶H的序列相似性差。突变分析表明，催化反应需要四个酸性残基，这是非常保守的1型核糖核酸酶H和多核苷酸转移酶家族的成员。因此，1型和2型RNA酶H似乎共享共同的催化机制，除了需要组氨酸作为前一种酶中的通用碱基。结合缺失突变体分析的结果，该结构表明2型RNase H的C-末端结构域参与与DNA/RNA杂合体的相互作用。
The catalytic center of an archaeal Type 2 RNase H has been identified by a combination of X-ray crystallographic and mutational analyses. The crystal structure of the Type 2 RNase H from Thermococcus kodakaraensis KOD1 has revealed that the N-terminal major domain adopts the RNase H fold, despite the poor sequence similarity to the Type 1 RNase H. Mutational analyses showed that the catalytic reaction requires four acidic residues, which are well conserved in the Type 1 RNase H and the members of the polynucleotidyl transferase family. Thus, the Type 1 and Type 2 RNases H seem to share a common catalytic mechanism, except for the requirement of histidine as a general base in the former enzyme. Combined with the results from deletion mutant analyses, the structure suggests that the C-terminal domain of the Type 2 RNase H is involved in the interaction with the DNA/RNA hybrid.