The interaction of the nucleotide-binding subunit B with subunit F is essential in coupling of ion pumping and ATP synthesis in A(1)A(O) ATP synthases. Here we provide structural and thermodynamic insights on the nucleotide binding to the surface of subunits B and F of Methanosarcina mazei Gö1 A(1)A(O) ATP synthase, which initiated migration to its final binding pocket via two transitional intermediates on the surface of subunit B. NMR- and fluorescence spectroscopy as well as ITC data combined with molecular dynamics simulations of the nucleotide bound subunit B and nucleotide bound B-F complex in explicit solvent, suggests that subunit F is critical for the migration to and eventual occupancy of the final binding site by the nucleotide of subunit B. Rotation of the C-terminus and conformational changes in subunit B are initiated upon binding with subunit F causing a perturbation that leads to the migration of ATP from the transition site 1 through an intermediate transition site 2 to the final binding site 3. This mechanism is elucidated on the basis of change in binding affinity for the nucleotide at the specific sites on subunit B upon complexation with subunit F. The change in enthalpy is further explained based on the fluctuating local environment around the binding sites.

中文翻译：

---

亚基 F 调节马氏甲烷八叠球菌 Gö1 的 A(1)A(O) ATP 合酶的核苷酸结合亚基 B 中的 ATP 结合和迁移。

核苷酸结合亚基 B 与亚基 F 的相互作用对于 A(1)A(O) ATP 合酶中离子泵和 ATP 合成的耦合至关重要。在这里，我们提供了关于与马氏甲烷八叠球菌 Gö1 A(1)A(O) ATP 合酶 B 和 F 亚基表面结合的核苷酸的结构和热力学见解，该酶通过表面上的两个过渡中间体启动迁移到其最终结合口袋。亚基 B. NMR 和荧光光谱以及 ITC 数据与显式溶剂中核苷酸结合亚基 B 和核苷酸结合 BF 复合物的分子动力学模拟相结合，表明亚基 F 对于迁移到最终结合并最终占据B亚基的核苷酸位点。