Roca J
Institut de Biologia Molecular de Barcelona, CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain.
J Mol Biol. 2001 Jan 19;305(3):441-50. doi: 10.1006/jmbi.2000.4307.
Type II DNA topoisomerases catalyze the transport of one DNA double helix through another. Here, by using a non-hydrolyzable analog of ATP, I examined the single-step DNA transport preferences of the yeast type II topoisomerase bound to positively and negatively supercoiled DNA rings. I found that negative supercoiling favors decatenation of DNA rings more than positive supercoiling. Conversely, positive supercoiling favors the catenation and knotting of DNA rings more than negative supercoiling. This vectorial effect of DNA supercoiling handedness supports a model in which type II topoisomerases can recognize three DNA segments, and highlights a novel influence of DNA supercoiling in global DNA topology.
II型DNA拓扑异构酶催化一条DNA双螺旋穿过另一条DNA双螺旋的过程。在此，我通过使用一种不可水解的ATP类似物，研究了与正超螺旋和负超螺旋DNA环结合的酵母II型拓扑异构酶的单步DNA转运偏好。我发现，负超螺旋比正超螺旋更有利于DNA环的解连环。相反，正超螺旋比负超螺旋更有利于DNA环的连环和打结。DNA超螺旋方向的这种矢量效应支持了一个模型，即II型拓扑异构酶可以识别三个DNA片段，并突出了DNA超螺旋在整体DNA拓扑结构中的一种新影响。
