Department of Microbiology and Biotechnology, College of Life Sciences, Northeast Agricultural University, No. 600 Changjiang Road, Xiangfang District, Harbin, 150030, China.
National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, 100101, China.
Nat Commun. 2022 Jun 9;13(1):3329. doi: 10.1038/s41467-022-31031-x.
In the central nervous system (CNS), excitatory amino acid transporters (EAATs) mediate the uptake of excitatory neurotransmitter glutamate and maintain its low concentrations in the synaptic cleft for avoiding neuronal cytotoxicity. Dysfunction of EAATs can lead to many psychiatric diseases. Here we report cryo-EM structures of human EAAT2 in an inward-facing conformation, in the presence of substrate glutamate or selective inhibitor WAY-213613. The glutamate is coordinated by extensive hydrogen bonds and further stabilized by HP2. The inhibitor WAY-213613 occupies a similar binding pocket to that of the substrate glutamate. Upon association with the WAY-213613, the HP2 undergoes a substantial conformational change, and in turn stabilizes the inhibitor binding by forming hydrophobic interactions. Electrophysiological experiments elucidate that the unique S441 plays pivotal roles in the binding of hEAAT2 with glutamate or WAY-213613, and the I464-L467-V468 cluster acts as a key structural determinant for the selective inhibition of this transporter by WAY-213613.
在中枢神经系统 (CNS) 中，兴奋性氨基酸转运体 (EAATs) 介导兴奋性神经递质谷氨酸的摄取，并维持其在突触间隙中的低浓度，以避免神经元细胞毒性。EAATs 的功能障碍可导致许多精神疾病。在这里，我们报告了人类 EAAT2 在内向构象下的冷冻电镜结构，存在底物谷氨酸或选择性抑制剂 WAY-213613。谷氨酸通过广泛的氢键协调，并通过 HP2 进一步稳定。抑制剂 WAY-213613 占据与底物谷氨酸相似的结合口袋。与 WAY-213613 结合后，HP2 发生了很大的构象变化，通过形成疏水相互作用来稳定抑制剂的结合。电生理实验阐明了独特的 S441 在 hEAAT2 与谷氨酸或 WAY-213613 的结合中起着关键作用，而 I464-L467-V468 簇作为 WAY-213613 对该转运体选择性抑制的关键结构决定因素。
