...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Biochemistry >Chlorella Virus Marburg Topoisomerase II: High DNA Cleavage Activity as a Characteristic of Chlorella Virus Type II Enzymes
【24h】

Chlorella Virus Marburg Topoisomerase II: High DNA Cleavage Activity as a Characteristic of Chlorella Virus Type II Enzymes

机译：小球藻病毒马尔堡拓扑异构酶II：高DNA裂解活性是小球藻病毒II型酶的特征

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

Although the formation of a covalent enzyme-cleaved DNA complex is a prerequisite for the essential functions of topoisomerase II,this reaction intermediate has the potential to destabilize the genome.Consequently,all known eukaryotic type II enzymes maintain this complex at a low steady-state level.Recently,however,a novel topoisomerase II was discovered in Paramecium bursaria chlorella virus-1(PBCV-1)that has an exceptionally high DNA cleavage activity [Fortune et al.(2001)J.Biol.Chem.276,24401-24408].If robust DNA cleavage is critical to the physiological functions of chlorella virus topoisomerase II,then this remarkable characteristic should be conserved throughout the viral family.Therefore,topoisomerase II from Chlorella virus Marburg-1(CVM-1),a distant family member,was expressed in yeast,isolated,and characterized.CVM-1 topoisomerase II is 1058 amino acids in length,making it the smallest known type II enzyme.The viral topoisomerase II displayed a high DNA strand passage activity and a DNA cleavage activity that was ~50-fold greater than that of human topoisomerase IIalpha.High DNA cleavage appeared to result from a greater rate of scission rather than promiscuous DNA site utilization,inordinately tight DNA binding,or diminished religation rates.Despite the fact that CVM-1 and PBCV-1 topoisomerase II share ~67% amino acid sequence identity,the two enzymes displayed clear differences in their DNA cleavage specificity/site utilization.These findings suggest that robust DNA cleavage is intrinsic to the viral enzyme and imply that chlorella virus topoisomerase II plays a physiological role beyond the control of DNA topology.
机译：尽管形成共价酶切割的DNA复合物是拓扑异构酶II基本功能的先决条件，但该反应中间体可能会破坏基因组的稳定性。因此，所有已知的II型真核生物酶都将这种复合物维持在低稳态然而，最近，在草履虫法小球藻小病毒-1（PBCV-1）中发现了一种新型的拓扑异构酶II，其具有极高的DNA切割活性[Fortune等人（2001）J.Biol.Chem.276,24401- [24408]。如果强大的DNA切割对于小球藻病毒拓扑异构酶II的生理功能至关重要，那么在整个病毒家族中都应保留这一显着特征。因此，来自遥远家族的小球藻病毒Marburg-1（CVM-1）的拓扑异构酶II CVM-1拓扑异构酶II的长度为1058个氨基酸，是已知的最小的II型酶。病毒拓扑异构酶II表现出高的DNA链通过活性且DNA切割活性比人拓扑异构酶IIα高约50倍。高DNA切割似乎是由于更高的切割速率而不是混杂的DNA位置利用率，过分紧密的DNA结合或降低的连接速率所致。 CVM-1和PBCV-1拓扑异构酶II共有约67％的氨基酸序列同一性，这两种酶在其DNA切割特异性/位点利用方面显示出明显的差异。这些发现表明健壮的DNA切割是病毒酶和内在酶的本质。暗示小球藻病毒拓扑异构酶II在DNA拓扑结构的控制之外起着生理作用。

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