NMR Studies of Alpha-Bungarotoxin-Acetylcholine Receptor Peptide Complexes

α-金环蛇毒素-乙酰胆碱受体肽复合物的 NMR 研究

• 批准号: 9104794
• 负责人: Vladimir Basus
• 金额: $ 26.7万
• 依托单位: University of California-San Francisco
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-09-01 至 1995-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9104794&HistoricalAwards=false
• 关键词: NMR; Studies; Alpha; Bungarotoxin; Acetylcholine

The nicotinic acetylcholine receptor is found at neuromuscular junctions, where its function is to depolarize muscle cells at the postsynaptic membrane, triggering muscle contraction. Depolarization occurs by channel opening, induced by the binding of acetylcholine, to allow the passage of small cations. Neurotoxins inhibit the binding of acetylcholine, by binding a large portion of the acetylcholine receptor -subunit, blocking at least part of the acetylcholine binding site. The best structure for the receptor is at the low resolution level of 22 A, using a combination of electron microscopy and x-ray diffraction data. NMR spectroscopy for this large membrane bound complex is clearly beyond current technological capabilities. However, peptides corresponding to the portion of the receptor near the acetylcholine binding site have been found to bind - bungarotoxin with about the same affinity as the entire - subunit binds this neurotoxin. It is proposed here to determine the structure of these peptides bound to -bungarotoxin, using two and three-dimensional NMR spectroscopy, including heteronuclear techniques with selective isotopic labeling. This will allow for the first time the details of the interactions between a portion of the acetylcholine receptor containing the major determinant of the neurotoxin binding site, and at least part of the acetylcholine binding site to be determined. By studying complexes formed with different peptides the relative importance of specific binding interactions between - bungarotoxin and the acetylcholine receptor, will be clarified. This will contribute to the general knowledge of non-covalent interactions between proteins.

烟碱乙酰胆碱受体存在于神经肌肉 连接处，其功能是将肌肉细胞 突触后膜引发肌肉收缩 去极化通过结合诱导的通道开放发生 乙酰胆碱，以允许小阳离子通过。 神经毒素通过结合A抑制乙酰胆碱的结合 大部分乙酰胆碱受体亚单位，阻断 至少部分乙酰胆碱结合位点。 最好的 受体的结构是在22的低分辨率水平 A，使用电子显微镜和x射线的组合 衍射数据 核磁共振波谱分析这个大的膜结合 这显然超出了目前的技术能力。 然而，对应于受体部分的肽 在乙酰胆碱结合位点附近发现 - 银环蛇毒素的亲和力与整个 - 亚基结合这种神经毒素。 这里建议确定 这些肽的结构结合-银环蛇毒素，使用 二维和三维NMR光谱，包括 选择性同位素标记的异源技术。 这 将第一次允许交互的细节 含有乙酰胆碱受体的一部分 神经毒素结合位点的主要决定簇，并且至少 乙酰胆碱结合位点的一部分。 通过 研究与不同肽形成的复合物， 之间特异性结合相互作用的重要性 - 银环蛇毒素和乙酰胆碱受体，将得到澄清。 这将有助于非共价键的一般知识 蛋白质之间的相互作用。