Energy Coupling in Type II Topoisomerases: Why Do They Hydrolyze ATP?

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• 作者：Andrew D. Bates ; Anthony Maxwell
• 刊名：Biochemistry
• 出版年：2007
• 出版时间：July 10, 2007
• 年：2007
• 卷：46
• 期：27
• 页码：7929 - 7941
• 全文大小：358K
• 年卷期：v.46,no.27(July 10, 2007)
• ISSN：1520-4995

文摘

Type II topoisomerases are essential enzymes in all cells. They help to solve the topologicalproblems of DNA by passing one double helix through a transient break in another, in a reaction coupledto the hydrolysis of ATP. Members of one class of the enzymes, DNA gyrases, are configured to carryout an intramolecular reaction, removing positive supercoiling and introducing negative supercoiling intocircular DNA using free energy derived from ATP hydrolysis. The nonsupercoiling class, including bacterialtopoisomerase IV and eukaryotic topoisomerase II enzymes, can carry out both intra- and intermolecularreactions, and their primary role is the unlinking (decatenation) of daughter replicons before partition. Inthese enzymes, ATP hydrolysis is coupled to a reduction in DNA complexity (catenation, supercoiling,and knotting) below the level expected at equilibrium. This review discusses our current understandingof the mechanisms behind the coupling of the energy of ATP hydrolysis to topological changes catalyzedby both of these classes of enzyme.