Schoeffler A J, Berger J M
Department of Molecular and Cell Biology, 237 Hildebrand Hall #3206, University of California, Berkeley, CA 94720-3206, USA.
Biochem Soc Trans. 2005 Dec;33(Pt 6):1465-70. doi: 10.1042/BST0331465.
DNA topos (topoisomerases) are complex, multisubunit enzymes that remodel DNA topology. Members of the type II topo family function by passing one segment of duplex DNA through a transient break in another, a process that consumes two molecules of ATP and requires the co-ordinated action of multiple domains. Recent structural data on type II topo ATPase regions, which activate and enforce the directionality of DNA strand passage, have highlighted how ATP physically controls the catalytic cycle of the enzyme. Structural and biochemical studies of specialized DNA-binding domains in two paralogous bacterial type IIA topos (DNA gyrase and topo IV) show how these enzymes selectively negatively supercoil or decatenate DNA. Taken together, these findings expand our understanding of how disparate functional elements work together to co-ordinate the type II topo mechanism.
DNA拓扑异构酶（拓扑酶）是复杂的多亚基酶，可重塑DNA拓扑结构。II型拓扑酶家族的成员通过使一段双链DNA穿过另一段双链DNA中的瞬时断裂来发挥作用，这一过程消耗两分子ATP，并需要多个结构域的协同作用。最近关于II型拓扑酶ATP酶区域的结构数据突出了ATP如何物理控制酶的催化循环，该区域可激活并强化DNA链通过的方向性。对两种同源细菌IIA型拓扑酶（DNA促旋酶和拓扑异构酶IV）中特殊DNA结合结构域的结构和生化研究表明了这些酶如何选择性地使DNA负超螺旋或解连环。综上所述，这些发现拓展了我们对于不同功能元件如何协同作用以协调II型拓扑酶机制的理解。
