Biosciences Institute, Newcastle University, Newcastle upon Tyne NE2 4HH, UK.
Department of Biosciences, Durham University, South Road, Durham DH1 3LE, UK.
Structure. 2022 Aug 4;30(8):1129-1145.e3. doi: 10.1016/j.str.2022.05.009. Epub 2022 Jun 3.
Human topoisomerase II beta (TOP2B) modulates DNA topology using energy from ATP hydrolysis. To investigate the conformational changes that occur during ATP hydrolysis, we determined the X-ray crystallographic structures of the human TOP2B ATPase domain bound to AMPPNP or ADP at 1.9 Å and 2.6 Å resolution, respectively. The GHKL domains of both structures are similar, whereas the QTK loop within the transducer domain can move for product release. As TOP2B is the clinical target of bisdioxopiperazines, we also determined the structure of a TOP2B:ADP:ICRF193 complex to 2.3 Å resolution and identified key drug-binding residues. Biochemical characterization revealed the N-terminal strap reduces the rate of ATP hydrolysis. Mutagenesis demonstrated residue E103 as essential for ATP hydrolysis in TOP2B. Our data provide fundamental insights into the tertiary structure of the human TOP2B ATPase domain and a potential regulatory mechanism for ATP hydrolysis.
人类拓扑异构酶 IIβ（TOP2B）利用 ATP 水解产生的能量调节 DNA 拓扑结构。为了研究在 ATP 水解过程中发生的构象变化，我们分别以 1.9Å 和 2.6Å 的分辨率测定了与人 TOP2B ATP 酶结构域结合的 AMPPNP 或 ADP 的人 TOP2B ATP 酶结构域的 X 射线晶体结构。两种结构的 GHKL 结构域相似，而在传感器结构域内的 QTK 环可以移动以释放产物。由于 TOP2B 是双二氧哌嗪类药物的临床靶点，我们还确定了 TOP2B:ADP:ICRF193 复合物的结构，分辨率为 2.3Å，并确定了关键的药物结合残基。生化特征分析显示 N 端带减少了 ATP 水解的速率。突变分析表明，残基 E103 对 TOP2B 中的 ATP 水解是必需的。我们的数据为人类 TOP2B ATP 酶结构域的三级结构以及 ATP 水解的潜在调节机制提供了基本的见解。
