Unraveling how Lipophilic Modulators Alter pLGIC Function via Interactions with the M4 Transmembrane Helix

项目摘要/摘要 马克·阿尔卡里奥医生是一名心胸麻醉师，他的长期目标是成为一名独立的医生- 研究离子通道中变构的分子机制的科学家。他的研究背景在 膜蛋白的计算生物物理学，重点是脂类和脂类对膜的影响 蛋白质结构和功能。他对五聚体配基门控离子通道(PLGIC)和 麻醉作用的机制。几种内源性脂质，包括神经类固醇、磷脂和脂肪 酸是pLGICs的强烈变构调节剂，已有研究表明，包括麻醉药在内的药物， 利用这些与生俱来的监管机制。目前还不清楚亲脂素是如何结合在细胞外的 蛋白质，改变通道功能和功能状态之间的平衡。这样的分子机制是 对于针对这一系列渠道的合理、基于结构的新药设计至关重要。要解决这个问题 知识差距，候选人将使用创新的分子动力学(MD)技术的组合来 原核生物pLGIC、ELIC(欧文氏菌配基门控离子)的状态依赖结构集合的特征 通道)和人7烟碱型乙酰胆碱受体(NAChR)。目标1将决定构象如何 对于面向脂质的，第四跨膜(M4)螺旋随通道的功能状态而变化(即，休息， 激活、不敏感)，使用计算电生理学方法。目标2将描述结合部位 二十二碳六烯酸(DHA)，一种多不饱和脂肪酸，以及DHA结合如何通过 多尺度模拟和自由能计算。这项工作将产生对国家依赖的新见解 PLGICs的动力学以及建立亲脂性变构调节的分子模型。这项研究将 在Wayland Cheng博士的指导下进行，他是pLGIC结构和功能方面的专家，重点是脂质结合 和调制，以及共同导师格雷斯·布兰尼根博士，他是一位专注于 膜蛋白分子动力学方法的发展及应用。一个咨询委员会由Dr。 麻醉药理学专家亚历克斯·埃弗斯，离子通道热力学专家巴伦·昌达博士 以及自由能计算专家Jerome Hénin博士将有助于 候选人。该研究计划将允许候选人发展自由能计算和 计算机电生理学，这将使他为离子通道的计算生物物理学的职业生涯做好准备。 此外，在该奖项期间参与职业发展活动将为候选人做好准备 在颁奖结束前独立。圣路易斯华盛顿大学麻醉学系， 作为麻醉学学术领域的领军人物，为离子通道研究提供了良好的支持环境 和内科科学家的发展。

Project Summary/Abstract Dr. Mark Arcario is a cardiothoracic anesthesiologist whose long-term goal is to be an independent physician- scientist studying molecular mechanisms of allostery in ion channels. His research background is in computational biophysics of membrane proteins with a focus on the effects of lipids and lipophiles on membrane protein structure and function. He has a special interest in pentameric ligand-gated ion channels (pLGICs) and mechanisms of anesthetic action. Several endogenous lipids, including neurosteroids, phospholipids, and fatty acids, are strong allosteric modulators of pLGICs and it has been suggested that drugs, including anesthetics, exploit these innate regulatory mechanisms. It is not well-known how lipophiles, which bind at the periphery of the protein, alter channel function and equilibrium between functional states. Such a molecular mechanism is essential for the rational, structure-based design of new drugs targeting this family of channels. To address this knowledge gap, the candidate will use a combination of innovative molecular dynamics (MD) techniques to characterize state-dependent structural ensembles of prokaryotic pLGIC, ELIC (Erwinia ligand-gated ion channel), and the human 7 nicotinic acetylcholine receptor (nAChR). Aim 1 will determine how the conformation of the lipid-facing, fourth transmembrane (M4) helix varies with the functional state of the channel (i.e., resting, activated, desensitized), using computational electrophysiology methods. Aim 2 will characterize the binding site of docosahexaenoic acid (DHA), a polyunsaturated fatty acid, and how binding of DHA causes inhibition using multiscale simulation and free energy calculations. This work will yield novel insight into state-dependent dynamics of pLGICs as well as establish a molecular model of lipophilic allosteric modulation. This research will be conducted under Dr. Wayland Cheng, an expert in pLGIC structure and function with a focus on lipid binding and modulation, along with co-mentor, Dr. Grace Brannigan, an expert in computational biophysics with a focus on MD method development and application to membrane proteins. An advisory committee comprised of Dr. Alex Evers, an expert in anesthetic pharmacology, Dr. Baron Chanda, an expert in ion channel thermodynamics and gating, and Dr. Jerome Hénin, an expert in free energy calculations, will aid in the scientific development of the candidate. The research plan will allow the candidate to develop skills in free energy calculations and computational electrophysiology, which will prepare him for a career in computational biophysics of ion channels. In addition, involvement in career development activities during this award will prepare the candidate for independence by the end of the award. The Department of Anesthesiology at Washington University in St. Louis, a leader in academic anesthesiology, provides an excellent and supportive environment for ion channel research and development of physician-scientists.