Chemical Synapses - Biophysical Studies

化学突触 - 生物物理研究

• 批准号: 7169596
• 负责人: Henry A. Lester
• 金额: $ 33.41万
• 依托单位: CALIFORNIA INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 1977
• 资助国家: 美国
• 起止时间: 1977-12-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7169596
• 关键词: Affect; Agonist; Alzheimer' s Disease; Amines; Amino Acids; Ammonium; Attention Deficit Disorder; Binding; Binding Sites; C-terminal; Cations; Charge; Chemical Synapse; Cholinergic Receptors; Collaborations; Coupled; Crohn' s disease; Data; Dose; Embryo; Energy Transfer; Esters; Event; Fluorescein; Fluoresceins; Fluorescence; Fluorescence Resonance Energy Transfer; Frontal Lobe Epilepsy; Health; Helix (Snails); Ion Channel; Kinetics; Lanthanoid Series Elements; Measurement; Measures; Molecular Conformation; Motion; Muscle; Mutation; N-terminal; Neurons; Nicotinic Receptors; Object Attachment; Pain; Parkinson Disease; Peptides; Pharmacotherapy; Preparation; Proline; Recording of previous events; Rest; Rhodamine; Rhodamines; Roentgen Rays; Rotation; Schizophrenia; Serotonin; Serotonin Receptors 5-HT-3; Side; Site; Speed; Structure; Sudden infant death syndrome; System; Tail; Testing; Tryptophan; Vertebral column; Xenopus oocyte; amino group; base; ear helix; insight; knowledge of results; nicotinic receptor alpha4beta2; receptor; receptor function; research study; response; smoking cessation

DESCRIPTION (provided by applicant): This project studies the structure and function of molecules in the Cys-loop receptor superfamily: the muscle nicotinic acetylcholine receptor (nAChR), the neuronal alpha4beta2 nAChR, and the serotonin 5-HT3 receptor. Hypothesis 1 states that three events occur in the following sequence at the agonist binding site, (a) The charged amine / ammonium group of the agonist is attracted to the site by a monopole-monopole interaction with fixed negative .charges on side chains, (b) For agonists with an amino group (not a quaternary ammonium group), this interaction is stabilized by an H-bond to the backbone carbonyl of the 149-150 peptide bond, (c) The earliest conformational change places the agonist in a cation-pi interaction at tryptophan alpha149. Hypothesis 2 states that ye M2-M3 linker undergoes a change in backbone conformation during gating. Hypothesis 3 states that during channel activation, the upper M2 helix of all five subunits re-orients with respect to neighboring helices. Hypothesis 4 states that the dynamic, history- dependent functional interaction between alpha4beta2 and P2X2 receptors occurs via the beta2-M3-M4 loop and the P2X2 C-terminal tail. Hypotheses 1 and 2 will be tested with macroscopic and single-channel electrophysiological assessments of receptors bearing unnatural amino-acid side chains and unnatural backbone linkages. Hypotheses 1, 3, and 4 will be tested in measurements based on direct fluorescence of tethered probes, fluorescence resonance energy transfer (FRET), and lanthanide-based resonance energy transfer (LRET). The resulting knowledge about acetylcholine receptors and 5-HT3 receptors may provide both pathophysiological insights and better drug therapies for health challenges including smoking cessation, Parkinson's disease, Alzheimer's disease, pain, Crohn's disease, sudden infant death syndrome, attention deficit disorder, autosomal dominant nocturnal frontal lobe epilepsy, and schizophrenia.

描述（由申请人提供）：本项目研究半胱氨酸环受体超家族中分子的结构和功能：肌肉烟碱乙酰胆碱受体（nAChR）、神经元α 4 β 2 nAChR和5-羟色胺5-HT 3受体。假设1指出，在激动剂结合位点按以下顺序发生三个事件：（a）激动剂的带电荷的胺/铵基团通过侧链上带有固定负电荷的胆甾醇-胆甾醇相互作用被吸引到该位点，（B）对于具有氨基的激动剂，（不是季铵基团），这种相互作用通过与149-150肽键的骨架羰基的H-键来稳定，（c）最早的构象变化使激动剂在色氨酸α 149处发生阳离子-π相互作用。假设2指出，M2-M3接头在门控期间经历骨架构象的变化。假设3指出，在通道激活期间，所有五个亚基的上部M2螺旋相对于相邻螺旋重新定向。假设4指出，α 4 β 2和P2 X2受体之间的动态的、历史依赖性的功能相互作用通过β 2-M3-M4环和P2 X2 C-末端尾发生。假设1和2将通过对带有非天然氨基酸侧链和非天然骨架连接的受体进行肉眼和单通道电生理学评估进行检验。假设1、3和4将在基于束缚探针的直接荧光、荧光共振能量转移（FRET）和基于镧系元素的共振能量转移（LRET）的测量中进行测试。关于乙酰胆碱受体和5-HT 3受体的知识可以为健康挑战提供病理生理学见解和更好的药物治疗，包括戒烟，帕金森病，阿尔茨海默病，疼痛，克罗恩病，婴儿猝死综合征，注意力缺陷障碍，常染色体显性夜间额叶癫痫和精神分裂症。