• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Molecular Biology >Role of divalent metal cations in ATP hydrolysis catalyzed by the hepatitis C virus NS3 helicase: Magnesium provides a bridge for ATP to fuel unwinding
【24h】

Role of divalent metal cations in ATP hydrolysis catalyzed by the hepatitis C virus NS3 helicase: Magnesium provides a bridge for ATP to fuel unwinding

机译：丙型肝炎病毒NS3解旋酶催化二价金属阳离子在ATP水解中的作用：镁为ATP提供了促进解开的桥梁

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

This study investigates the role of magnesium ions in coupling ATP hydrolysis to the nucleic acid unwinding catalyzed by the NS3 protein encoded by the hepatitis C virus (HCV). Analyses of steady-state ATP hydrolysis rates at various RNA and magnesium concentrations were used to determine values for the 15 dissociation constants describing the formation of a productive enzyme-metal-ATP-RNA complex and the four rate constants describing hydrolysis of ATP by the possible enzyme-ATP complexes. These values coupled with direct binding studies, specificity studies and analyses of site-directed mutants reveal only one ATP binding site on HCV helicase centered on the catalytic base Glu291. An adjacent residue, Asp290, binds a magnesium ion that forms a bridge to ATP, reorienting the nucleotide in the active site. RNA stimulates hydrolysis while decreasing the affinity of the enzyme for ATP, magnesium, and MgATP. The binding scheme described here explains the unusual regulation of the enzyme by ATP that has been reported previously. Binding of either free magnesium or free ATP to HCV helicase competes with MgATP, the true fuel for helicase movements, and leads to slower hydrolysis and nucleic acid unwinding. (c) 2006 Elsevier Ltd. All rights reserved.
机译：这项研究调查了镁离子在ATP水解与丙型肝炎病毒（HCV）编码的NS3蛋白催化的核酸解链偶联中的作用。使用各种RNA和镁浓度下的稳态ATP水解速率分析来确定15个解离常数的值，这些解离常数描述了生产性酶-金属-ATP-RNA复合物的形成，而四个速率常数描述了可能的ATP水解酶-ATP复合物。这些值加上直接结合研究，特异性研究和定点突变体的分析显示，HCV解旋酶上只有一个ATP结合位点位于催化碱基Glu291上。相邻的残基Asp290与镁离子结合，形成与ATP的桥，从而重新定位活性位点中的核苷酸。 RNA刺激水解，同时降低了酶对ATP，镁和MgATP的亲和力。这里描述的结合方案解释了先前报道的ATP对酶的异常调节。游离镁或游离ATP与HCV解旋酶的结合会与MgATP竞争，MgATP是解旋酶运动的真正燃料，并导致水解速度减慢和核酸解旋。 （c）2006 Elsevier Ltd.保留所有权利。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号