Intrinsic Motions in the N-Terminal Domain of an Ionotropic Glutamate Receptor Detected by Fluorescence Correlation Spectroscopy
Intrinsic Motions in the N-Terminal Domain of an Ionotropic Glutamate Receptor Detected by Fluorescence Correlation Spectroscopy
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DOI：
10.1016/j.jmb.2011.09.037
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发表时间：
2011-11-18
影响因子：
5.6
通讯作者：
Neuweiler, Hannes
中科院分区：
文献类型：
--
作者：
Jensen, Mette H.;Sukumaran, Madhav;Neuweiler, Hannes
离子型谷氨酸受体 (iGluR) 介导中枢神经系统的兴奋性神经传递，在大脑发育和疾病中发挥关键作用。 iGluR 具有两个不同的胞外结构域，但远端 N 末端结构域 (NTD) 的功能作用尚不清楚。一些非 N-甲基-D-天冬氨酸 (NMDA) iGluR 的 NTD 晶体结构与促进受体组装的刚体一致，但表明可以调节信号传导的额外动态作用。在这里，我们通过采用外在恶嗪荧光波动的相关分析，超越了传统蛋白质单分子光谱的空间和时间限制。我们观察到 AMPA 型 iGluR NTD 区域内环段和螺旋的纳秒 (ns) 到微秒 (μ s) 运动，该区域先前已被确定为结构可变的。我们的数据显示 AMPA 受体 NTD 经历快速构象波动，表明该结构域除了其已建立的组装功能之外还具有固有的变构能力。 2011 爱思唯尔有限公司保留所有权利。
Ionotropic glutamate receptors (iGluRs) mediate excitatory neurotransmission in the central nervous system and play key roles in brain development and disease. iGluRs have two distinct extracellular domains, but the functional role of the distal N-terminal domain (NTD) is poorly understood. Crystal structures of the NTD from some non-N-methyl-D-aspartate (NMDA) iGluRs are consistent with a rigid body that facilitates receptor assembly but suggest an additional dynamic role that could modulate signaling. Here, we moved beyond spatial and temporal limitations of conventional protein single-molecule spectroscopy by employing correlation analysis of extrinsic oxazine fluorescence fluctuations. We observed nanosecond (ns)-to-microsecond (mu s) motions of loop segments and helices within a region of an AMPA-type iGluR NTD, which has been identified previously to be structurally variable. Our data reveal that the AMPA receptor NTD undergoes rapid conformational fluctuations, suggesting an inherent allosteric capacity for this domain in addition to its established assembly function. 2011 Elsevier Ltd. All rights reserved.