Basis for the discrimination of supercoil handedness during DNA cleavage by human and bacterial type II topoisomerases.
Basis for the discrimination of supercoil handedness during DNA cleavage by human and bacterial type II topoisomerases.
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人类和细菌 II 型拓扑异构酶 DNA 切割过程中超螺旋旋向判别的基础。
DOI：
10.1093/nar/gkad190
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发表时间：
2023
影响因子：
14.9
通讯作者：
Osheroff,Neil
中科院分区：
文献类型：
--
作者：
Jian,JeffreyY;McCarty,KevinD;Byl,JoAnnW;Guengerich,FPeter;Neuman,KeirC;Osheroff,Neil
为了进行双链DNA通过，II型拓扑异构酶产生共价酶切割的DNA复合物（即切割复合物）。虽然这种复合物是一种必需的酶中间体，但它对基因组稳定性也有内在的危险。因此，裂解复合物是几种临床相关抗癌和抗菌药物的靶点。人拓扑异构酶IIα和IIβ以及细菌促旋酶与负超螺旋DNA底物的切割复合物水平高于正超螺旋DNA底物。相反，细菌拓扑异构酶IV不太能够区分DNA超螺旋手性。尽管超螺旋几何结构对II型拓扑异构酶活性的重要性，但在DNA切割过程中超螺旋手性识别的基础尚未被表征。基于台式和快速淬灭流动动力学实验的结果，切割的正向速率是拓扑异构酶IIα/IIβ、促旋酶和拓扑异构酶IV在不存在或存在抗癌/抗菌药物的情况下如何区分超螺旋手性的决定因素。在药物的存在下，这种能力可以通过与负超螺旋DNA形成更稳定的切割复合物来增强。最后，酶介导的DNA连接的速率不有助于在切割过程中识别DNA超螺旋几何形状。我们的研究结果提供了更深入的了解II型拓扑异构酶如何识别它们的DNA底物。
To perform double-stranded DNA passage, type II topoisomerases generate a covalent enzyme-cleaved DNA complex (i.e. cleavage complex). Although this complex is a requisite enzyme intermediate, it is also intrinsically dangerous to genomic stability. Consequently, cleavage complexes are the targets for several clinically relevant anticancer and antibacterial drugs. Human topoisomerase IIα and IIβ and bacterial gyrase maintain higher levels of cleavage complexes with negatively supercoiled over positively supercoiled DNA substrates. Conversely, bacterial topoisomerase IV is less able to distinguish DNA supercoil handedness. Despite the importance of supercoil geometry to the activities of type II topoisomerases, the basis for supercoil handedness recognition during DNA cleavage has not been characterized. Based on the results of benchtop and rapid-quench flow kinetics experiments, the forward rate of cleavage is the determining factor of how topoisomerase IIα/IIβ, gyrase and topoisomerase IV distinguish supercoil handedness in the absence or presence of anticancer/antibacterial drugs. In the presence of drugs, this ability can be enhanced by the formation of more stable cleavage complexes with negatively supercoiled DNA. Finally, rates of enzyme-mediated DNA ligation do not contribute to the recognition of DNA supercoil geometry during cleavage. Our results provide greater insight into how type II topoisomerases recognize their DNA substrates.