NMR study of general anesthetic interaction with nAChR β2 subunit
NMR study of general anesthetic interaction with nAChR β2 subunit
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DOI：
10.1529/biophysj.107.116772
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发表时间：
2008-03-01
影响因子：
3.4
通讯作者：
Tang, Pei
中科院分区：
文献类型：
--
作者：
Bondarenko, Vasyl;Yushmanov, Victor E.;Tang, Pei
通过 H-1 和 N-15 溶液态 NMR 测定麻醉剂对十二烷基磷酸胆碱 (DPC) 胶束中的 62 亚基人神经元烟碱乙酰胆碱受体 (nAChR) 的第二跨膜结构域 (TM2e) 的结构和动力学的影响，探索了麻醉剂与膜蛋白相互作用的分子基础。 1-氯-1,2,2-三氟环丁烷 (F3) 和异氟烷这两种挥发性全身麻醉剂都会引起 TM2e 残基之间化学位移的不均匀变化。饱和转移差核磁共振实验进一步证实了麻醉剂与TM2e的直接相互作用。在螺旋 C 末端的三个亮氨酸残基上观察到显着且更特异的麻醉相互作用。尽管添加麻醉剂后 TM2e 螺旋结构仍然存在，但主链酰胺化学位移的周期性变化证明了螺旋氢键的合理缩短和延长。 TM2e 主链动力学是根据 N-15 弛豫率常数、R-1 和 R-2 以及 N-15-[H-1] NOE 使用无模型方法确定的。在麻醉剂存在下，胶束中 TM2e 的整体翻滚时间（11.7 ns）略有增加（类似于 12.3-12.5 ns）。所有 N-15 标记残基的顺序参数 S-2 都超过 0.9，显示内部运动受限。麻醉剂似乎对 TM2e 的内部运动影响较小。该研究为后续更全面地研究麻醉剂对神经元 nAChR 跨膜域复合物的影响奠定了基础。
The molecular basis of anesthetic interaction with membrane proteins has been explored via determination of anesthetic effects on the structure and dynamics of the extended second transmembrane domain (TM2e) of the human neuronal nicotinic acetylcholine receptor (nAChR),62 subunit in dodecylphosphocholine (DPC) micelles by H-1 and N-15 solution-state NMR. Both 1-chloro-1,2,2-trifluorocyclobutane (F3) and isoflurane, two volatile general anesthetics, induced nonuniform changes in chemical shifts among residues in TM2e. Saturation transfer difference NMR experiments further confirmed the direct anesthetic interaction with TM2e. A significant and more specific anesthetic interaction was observed on three leucine residues at the helix C-terminus. Although the TM2e helical structure remained after addition of anesthetics, plausible shortening and lengthening of helix hydrogen bonds were evidenced by periodic changes in backbone amide chemical shifts. TM2e backbone dynamics were determined on the basis of the N-15 relaxation rate constants, R-1 and R-2, and the N-15-[H-1] NOE using the model-free approach. The global tumbling time (11.7ns) of TM2e in micelles slightly increased (similar to 12.3-12.5 ns) in the presence of anesthetics. The order parameter, S-2, exceeded 0.9 for all N-15-labeled residues, showing a restricted internal motion. Anesthetics appear to have minor effect on the TM2e's internal motion. This study provided the basis for subsequent more comprehensive studies of anesthetic effects on the transmembrane domain complex of neuronal nAChR.