Type II topoisomerase
（重定向自Topoisomerase II）
![Structure of the 42 KDa fragment of the N-terminal ATPase and transducer domains of DNA gyrase homologous to all other type IIA topoisomerases.](/Images/godic/202502/16/Gyr5411.PNG")
![Structure of yeast topoisomerase II bound to a doubly nicked 34-mer duplex DNA (PDB ID =2RGR). The Toprim fold is colored cyan; the DNA is colored orange; the HTH is colored magenta; and the C-gate is colored purple. Notice that the DNA is bent by ~160 degrees through an invariant isoleucine (Ile833 in yeast).](/Images/godic/202502/16/2rgr5411.png")
![Structure of topo VI (PDB ID =2Q2E). Monomers are colored differently. The N-terminal ATPase domain lies on the top of the molecule, forming the DNA gate, while the DNA gate lies on the bottom.](/Images/godic/202502/16/TopoVI5411.png")
Type II topoisomerases cut both strands of the DNA helix simultaneously in order to manage DNA tangles and supercoils. They use the hydrolysis of ATP, unlike Type I topoisomerase. In this process, these enzymes change the linking number of circular DNA by ±2.