Topoisomerase V relaxes supercoiled DNA by a constrained swiveling mechanism
Topoisomerase V relaxes supercoiled DNA by a constrained swiveling mechanism
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DOI：
10.1073/pnas.0701989104
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发表时间：
2007-09-11
影响因子：
11.1
通讯作者：
Mondragon, Alfonso
中科院分区：
文献类型：
--
作者：
Taneja, Bhupesh;Schnurr, Bernhard;Mondragon, Alfonso
拓扑异构酶 V 是一种 I 型拓扑异构酶，与其他拓扑异构酶没有结构或序列相似性。尽管它属于拓扑异构酶的 I 型亚家族，但与 IA 型或 IB 型酶无关。我们使用实时单分子微机械实验表明，拓扑异构酶 V 通过释放多个 DNA 转角的事件来松弛 DNA，采用类似于 IB 型酶的受限旋转机制。松弛由超螺旋 DNA 中的扭矩提供动力，并受到蛋白质和 DNA 之间的摩擦力的约束。尽管所有 IB 型酶具有共同的结构和机制，并且 IA 型和 II 型酶显示出明显的结构和功能相似性，但拓扑异构酶 V 代表了一种不同类型的拓扑异构酶，它以与 IB 型分子相似的整体方式松弛 DNA，但使用完全不同的结构和机制框架。
Topoisomerase V is a type I topoisomerase without structural or sequence similarities to other topoisomerases. Although it belongs to the type I subfamily of topoisomerases, it is unrelated to either type IA or IB enzymes. We used real-time single-molecule micromechanical experiments to show that topoisomerase V relaxes DNA via events that release multiple DNA turns, employing a constrained swiveling mechanism similar to that for type IB enzymes. Relaxation is powered by the torque in the supercoiled DNA and is constrained by friction between the protein and the DNA. Although all type IB enzymes share a common structure and mechanism and type IA and type II enzymes show marked structural and functional similarities, topoisomerase V represents a different type of topoisomerase that relaxes DNA in a similar overall manner as type IB molecules but by using a completely different structural and mechanistic framework.