1. 重组蛋白
  2. Enzymes & Regulators
  3. Topoisomerase

Topoisomerase  (拓扑异构酶)

DNA 拓扑异构酶是操纵所有细胞中 DNA 拓扑结构的酶,在 DNA 复制、转录、染色体分离和重组中发挥重要作用。 此外,这些酶对 DNA 超卷的稳态水平进行微调,以促进蛋白质与 DNA 的相互作用,并防止有害的过度超卷。DNA拓扑异构酶普遍存在于细菌、古细菌和真核生物中。 所有细胞都含有两种主要形式的拓扑异构酶,I 型拓扑异构酶在 DNA 中进行单链切割,II 型拓扑异构酶切割双链 DNA。 I 型拓扑异构酶无需外部能量来源 (如 ATP 水解) 就能改变 DNA 的拓扑结构。 然而,所有 II 型拓扑异构酶水解 ATP 作为其催化反应循环的一部分。DNA 拓扑异构酶是几种已批准的和实验性的抗癌药物的重要靶点。

DNA topoisomerases are enzymes that manipulate the topology of DNA in all cells and play essential roles in DNA replication, transcription, chromosome segregation, and recombination. In addition, these enzymes fine-tune the steady-state level of DNA supercoiling both to facilitate protein interactions with the DNA and to prevent excessive supercoiling that is deleterious. DNA topoisomerases are found in all three domains of life (bacteria, archaea and eukarya). All cells contain two major forms of topoisomerase, type I topoisomerases, which makes single-stranded cuts in DNA, and type II topoisomerases, which cuts and passes double-stranded DNA. Type I topoisomerases change the topology of DNA without the need of an external source of energy, such as ATP hydrolysis. However, all type II topoisomerases hydrolyse ATP as part of their catalytic reaction cycle. DNA topoisomerases are important targets of several approved and experimental anti-cancer agents.

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