Probing allosteric surfaces of NMDA receptors

描述（由申请人提供）：许多内源性和合成配体调节NMDA受体活性，是许多神经系统疾病治疗干预的潜在候选物。到目前为止，经验性的尝试，以控制enaminNMDA受体介导的流量只有适度的成功，在临床上，主要是由于不够了解的机制，管理的变构控制的NMDA受体的活动和发挥的具体作用，这些活动在脑生理和病理。在过去的资助期间，目标是描绘内源性调节剂（质子，锌/艾芬地尔，甘氨酸）影响NMDA受体门控动力学的机制，从而控制与突触信号相关的宏观反应。在下一个资助期间，目标是描绘构成NMDA受体激活的细胞内蛋白质运动。一般的方法是利用最近解决的GluA 2四聚体受体，NMDA受体同源物和我们不断增长的专业知识NMDA受体门控调制的原子分辨率结构。我们将引入突变来扰乱（增加和减少）NMDA受体结构模块的相对迁移率，并通过单分子信号的动力学分析来描绘伴随的反应机制变化。此外，我们将探索从具有受限或增强的内部运动的受体获得的宏观响应的时间过程，以更好地理解特定的结构特征如何支持NMDA受体在脑生理学和病理学中发挥的独特生物学功能。总体而言，这项工作将提供关键信息的NMDA受体激活的结构相关性，并将整合目前孤立的结构和动力学模型的门控。鉴于谷氨酸受体介导大脑中超过90%的兴奋性传递，并且NMDA受体对许多基本的大脑功能至关重要，因此所提出的实验产生的知识可能对神经传递和神经调节领域产生广泛的影响。

DESCRIPTION (provided by applicant): Numerous endogenous and synthetic ligands modulate NMDA receptor activities and are potential candidates for therapeutic intervention in a number of neurologic disorders. To date, empirical attempts to control en masse NMDA receptor-mediated fluxes have had only modest success in the clinic, mainly due to inadequate understanding of the mechanisms governing the allosteric control of NMDA receptor activities and of the specific roles played by these activities in brain physiology and pathology. Over the previous funding period the objective has been to delineate the mechanisms by which endogenous modulators (protons, zinc/ifenprodil, glycine) affect NMDA receptor gating dynamics and thus control the macroscopic response relevant to synaptic signaling. Over the next funding period the objective is to delineate the intracellular protein motions that constitute the NMDA receptor activation. The general approach is to capitalize on the recently solved atomic-resolution structure for a GluA2 tetrameric receptor, a NMDA receptor homologue and our growing expertise on NMDA receptor gating modulation. We will introduce mutations to perturb (increase and decrease) the relative mobility of NMDA receptor structural modules and will delineate the accompanying changes in reaction mechanism by kinetic analyses of single-molecule signals. Further, we will explore the time course of macroscopic responses obtained from receptors with restricted or enhanced internal motions to better understand how specific structural features support the unique biological functions played by NMDA receptors in brain physiology and pathology. Overall this work will provide critical information about structural correlates of NMDA receptor activation and will integrate the currently isolated structural and kinetic models of gating. Given that glutamate receptors mediate more than 90% of excitatory transmission in brain and NMDA receptors are critical to many fundamental brain functions, knowledge generated by the proposed experiments is likely to have wide impact on the fields of neurotransmission and neuromodulation.