Engineering a Transmitter Binding Site

项目概要/摘要 生物医学的一个基本原理是小分子可以结合到特定的 受体来触发生理反应。我们试图理解 发生在神经递质结合位点的分子事件， 神经肌肉乙酰胆碱受体，当这个通道'门'之间的非传导 和离子传导构象。这些知识将帮助我们理解 配体-蛋白质复合物的生物物理机制，并将提高我们的能力， 为烟碱（和其他）受体设计新药。基于结构的药物发现 药物作用取决于配体的不同结合 受体的非活性构象和活性构象。为了解决这一点，我们将使用 单通道电生理学和动力学分析来研究非配体门控， 将使我们能够测量所有的显着激活平衡常数， 确定侧链在两个发射器中的每一个上的能量贡献 结合位点。我们还将估计小配体探针的差异结合能， 在野生型和突变型受体中。最终，这些知识将被用于 工程化乙酰胆碱受体，其可预测地响应于任意配体。

PROJECT SUMMARY/ABSTRACT A fundamental principle of biomedicine is that small molecules can bind to specific receptors to trigger physiological responses. We seek to understand the energetic nature of the molecular events that occur at the neurotransmitter binding sites of the neuromuscular acetylcholine receptor when this channel 'gates' between non-conducting and ion-conducting conformations. This knowledge will help us understand the biophysical mechanisms of ligand-protein complexes, and will advance our ability to design new drugs for nicotinic (and other) receptors. Structure-based drug discovery should incorporate the fact that drug action depends on the differential binding of ligands to inactive vs. active conformations of a receptor. To address this point we will use single-channel electrophysiology and kinetic analysis to study unliganded gating, which will allow us to measure all of the salient activation equilibrium constants and to ascertain the energetic contributions of the side chains at each of the two transmitter binding sites. We will also estimate differential binding energies for small ligand probes, in both wild type and mutant receptors. Eventually, this knowledge will be used to engineer acetylcholine receptors that respond predictably to arbitrary ligands.