High Conformational Variability in the GluK2 Kainate Receptor Ligand-Binding Domain.
High Conformational Variability in the GluK2 Kainate Receptor Ligand-Binding Domain.
复制标题
GluK2 红藻氨酸受体配体结合域的高构象变异性。
DOI：
10.1016/j.str.2018.09.008
复制
发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Lau,AlbertY
中科院分区：
文献类型：
--
作者：
Wied,TylerJ;Chin,AlfredC;Lau,AlbertY
离子型谷氨酸受体（iGluRs）的红藻氨酸家族介导突触前和突触后神经传递。先前计算的iGluR配体结合结构域（LBD）的平均力构象势（PMF）揭示了α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）和N-甲基-D-天冬氨酸（NMDA）iGluR亚家族之间的亚型依赖性构象差异。在这里，我们报告的红藻氨酸受体GluK 2在载脂蛋白和谷氨酸结合状态的PMFs。载脂蛋白和谷氨酸结合的GluK 2 LBD优先进入闭合裂缝构象。载脂蛋白GluK 2表现出令人惊讶的高度构象灵活性，进入开放和闭合状态。比较iGluR亚型，这些结果与甘氨酸结合GluN 1和GluN 3A NMDA亚基相似，与谷氨酸结合GluA 2和GluN 2A亚基不同。为了测试跨叶相互作用对闭合裂缝LBD稳定性的贡献，我们计算了两个GluK 2突变体D462 A和D 656 S的PMF。D462 A，而不是D 656 S，削弱了谷氨酸结合的LBD的闭合裂缝构象。理论玻尔兹曼加权的小角度X射线散射轮廓改善协议与实验结果相比，从LBD晶体结构单独的计算。
The kainate family of ionotropic glutamate receptors (iGluRs) mediates pre- and postsynaptic neurotransmission. Previously computed conformational potentials of mean force (PMFs) for iGluR ligand-binding domains (LBDs) revealed subtype-dependent conformational differences between α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and N-methyl-D-aspartic acid (NMDA) iGluR subfamilies. Here we report PMFs for the kainate receptor GluK2 in apo and glutamate-bound states. Apo and glutamate-bound GluK2 LBDs preferentially access closed-cleft conformations. Apo GluK2 exhibits a surprisingly high degree of conformational flexibility, accessing open and closed states. Comparing across iGluR subtypes, these results are similar to glycine-binding GluN1 and GluN3A NMDA subunits and differ from glutamate-binding GluA2 and GluN2A subunits. To test the contribution of cross-lobe interactions on closed-cleft LBD stability, we computed PMFs for two GluK2 mutants, D462A and D656S. D462A, but not D656S, weakens closed-cleft conformations of the glutamate-bound LBD. Theoretical Boltzmann-weighted small-angle X-ray scattering profiles improve agreement with experimental results compared with calculations from the LBD crystal structure alone.