Structural basis of gate-DNA breakage and resealing by type II topoisomerases.
Structural basis of gate-DNA breakage and resealing by type II topoisomerases.
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DOI：
10.1371/journal.pone.0011338
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发表时间：
2010-06-28
期刊：
影响因子：
3.7
通讯作者：
Sanderson MR
中科院分区：
文献类型：
--
作者：
Laponogov I;Pan XS;Veselkov DA;McAuley KE;Fisher LM;Sanderson MR
II型DNA拓扑异构酶是一种普遍存在的酶，在DNA复制、重组和转录中具有重要功能。它们通过与门-DNA双链形成瞬时共价切割复合体来改变DNA拓扑，从而允许第二个双链通过门运输。尽管它具有重要的生物学意义，并被抗癌和抗菌药物靶向，但对任何II型酶的切割复合体的形成和逆转尚不清楚。为了解决这一机制，我们使用X射线结晶学来研究肺炎链球菌拓扑异构酶IV形成和逆转DNA切割复合体的顺序状态。肺炎链球菌拓扑异构酶IV是参与染色体分离的细菌II型酶。由新的抗菌二酮捕获的复合体的高分辨率结构显示，两个药物分子嵌入在切割的B-型DNA门上，并通过药物特异的蛋白质接触锚定。Dione释放产生了不含药物的裂解和重新密封的DNA复合体，其中DNA门采用不寻常的A/B型螺旋构象，镁离子重新定位，以配位每个剪刀状的磷酸二酯基团，并促进活性部位酪氨酸的可逆切割。这些结构是II型拓扑异构酶的第一个可能的反应中间产物，表明II型酶如何在其正常的反应周期中重新密封DNA，并阐明了药物阻止的一些方面，这些方面对开发新的拓扑异构酶靶向治疗很重要。
Type II DNA topoisomerases are ubiquitous enzymes with essential functions in DNA replication, recombination and transcription. They change DNA topology by forming a transient covalent cleavage complex with a gate-DNA duplex that allows transport of a second duplex though the gate. Despite its biological importance and targeting by anticancer and antibacterial drugs, cleavage complex formation and reversal is not understood for any type II enzyme. To address the mechanism, we have used X-ray crystallography to study sequential states in the formation and reversal of a DNA cleavage complex by topoisomerase IV from Streptococcus pneumoniae, the bacterial type II enzyme involved in chromosome segregation. A high resolution structure of the complex captured by a novel antibacterial dione reveals two drug molecules intercalated at a cleaved B-form DNA gate and anchored by drug-specific protein contacts. Dione release generated drug-free cleaved and resealed DNA complexes in which the DNA gate instead adopts an unusual A/B-form helical conformation with a Mg2+ ion repositioned to coordinate each scissile phosphodiester group and promote reversible cleavage by active-site tyrosines. These structures, the first for putative reaction intermediates of a type II topoisomerase, suggest how a type II enzyme reseals DNA during its normal reaction cycle and illuminate aspects of drug arrest important for the development of new topoisomerase-targeting therapeutics.
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DOI：
10.1038/nrc2607
发表时间：
2009-05
期刊：
Nature reviews. Cancer
影响因子：
--
作者：
通讯作者：
--
影响因子：
3.7
作者：
Laponogov I;Pan XS;Veselkov DA;McAuley KE;Fisher LM;Sanderson MR
通讯作者：
Sanderson MR
影响因子：
14.9
作者：
Sissi C;Palumbo M
通讯作者：
Palumbo M
DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
64.8
作者：
Dong, Ken C.;Berger, James M.
通讯作者：
Berger, James M.