Metal binding and activation of the ribonuclease H domain from moloney murine leukemia virus.
Metal binding and activation of the ribonuclease H domain from moloney murine leukemia virus.
复制标题
莫洛尼鼠白血病病毒核糖核酸酶 H 结构域的金属结合和激活。
DOI：
10.1093/protein/12.11.975
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
Marqusee,S
中科院分区：
文献类型：
--
作者：
Goedken,ER;Marqusee,S
The RNase H family of enzymes degrades RNA in RNA˙DNA hybrids in a divalent cation-dependent manner. RNases H from diverse sources such asEscherichia coliand human immunodeficiency virus (HIV) share homologous metal-binding active sites, and the activity of the RNase H domain of reverse transcriptase (RT) is required for retroviral replication. The isolated RNase H domain from HIV RT, however, is inactive. In contrast, the RNase H domain of Moloney murine leukemia virus (MMLV) is active, enabling functional studies. Unlike bothE.coliRNase HI and HIV RT, the RNase H activity of MMLV RT shows greater activity in Mn2+than Mg2+. We investigated the effect of mutations in five conserved active-site residues of the isolated MMLV RNase H domain. Mutations in two carboxylates eliminate metal binding while mutations in other active-site residues allow retention of metal ion affinity. Mutations that inactivateE.coliRNase HI in Mg2+have similar effects on the Mn2+-dependent activity of MMLV RNase H. These results suggest a similar one-metal catalytic mechanism for the Mn2+- and Mg2+-dependent activities of both prokaryotic and retroviral ribonucleases H.
