PHOTOLABELING OF ACETYLCHOLINE BINDING PROTEIN BY NICOTINOIDS & NEONICOTINOIDS

烟碱类化合物对乙酰胆碱结合蛋白进行光标记

• 批准号: 7957403
• 负责人: JOHN E CASIDA
• 金额: $ 0.43万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7957403
• 关键词: Acetylcholine; Agonist; Amino Acids; Binding; Binding Proteins; Binding Sites; Cations; Cholinergic Receptors; Complex; Computer Retrieval of Information on Scientific Projects Database; Funding; Goals; Grant; Homo; Insecta; Insecticides; Institution; Ion Channel; Label; Ligands; Mammals; Mass Spectrum Analysis; Modeling; Molecular; Nicotinic Receptors; Nitrogen; Oxygen; Pharmaceutical Preparations; Property; Research; Research Personnel; Resources; Source; United States National Institutes of Health; base; design; epibatidine; imidacloprid; pharmacophore

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Acetylcholine (ACh) binding protein (AChBP) is the model/surrogate of the extra cellular domain for the nicotinic ACh receptor/ion channel complex (nAChR). As with the extra cellular domain of nAChR, the AChBP has five binding pockets for ACh or drug. The AChBP is assembled with five homologous subunits (homo-pentamer) and the ACh binding site exists on the interface region between subunits.Mammalian selective nAChR agonist epibatidine (EPI) and insect nAChR selective agonist imidacloprid (IMI, the representative neonicotinoid insecticide) share some common structural moieties, but they are distinctly different in their physicochemical properties. EPI has a protonated nitrogen atom (cation), but IMI has a non-protonatable and electronegative nitro (NO2) pharmacophore. These structural differences determine the selectivity between mammals and insects. As a proof, if IMI loses the nitro group (desnitro-IMI), it is now a mammalian selective compound.Therefore, amino acid residue(s) interacting with the cation of EPI and the electronegative nitro oxygen(s) of IMI must be quite different even if both compounds are buried in the identical hole, i.e., the binding orientations are different. To approach the molecular basis for the selective interaction, we designed and prepared two types of photoaffinity ligands. Therefore, the experimental goals of this study involving the LC/MS/MS analyses are to identify specific amino acid residue(s) labeled by these two types of photoaffinity ligands.

该子项目是利用该技术的众多研究子项目之一 资源由 NIH/NCRR 资助的中心拨款提供。子项目和 研究者 (PI) 可能已从 NIH 的另一个来源获得主要资金， 因此可以在其他 CRISP 条目中表示。列出的机构是 对于中心来说，它不一定是研究者的机构。 乙酰胆碱 (ACh) 结合蛋白 (AChBP) 是烟碱型 ACh 受体/离子通道复合物 (nAChR) 细胞外结构域的模型/替代物。 与 nAChR 的细胞外结构域一样，AChBP 有五个用于 ACh 或药物的结合袋。 AChBP由五个同源亚基（同源五聚体）组装而成，ACh结合位点存在于亚基之间的界面区域。哺乳动物选择性nAChR激动剂皮巴替丁（EPI）和昆虫nAChR选择性激动剂吡虫啉（IMI，代表性新烟碱类杀虫剂）具有一些共同的结构部分，但它们在物理化学上有明显不同 特性。 EPI 具有质子化氮原子（阳离子），但 IMI 具有不可质子化且带负电的硝基 (NO2) 药效团。 这些结构差异决定了哺乳动物和昆虫之间的选择性。 作为证明，如果IMI失去硝基（脱硝基-IMI），它现在是哺乳动物选择性化合物。因此，即使两种化合物埋在相同的孔中，与EPI的阳离子和IMI的带负电的硝基氧相互作用的氨基酸残基也一定是完全不同的，即结合方向不同。 为了探究选择性相互作用的分子基础，我们设计并制备了两种类型的光亲和配体。因此，本研究涉及 LC/MS/MS 分析的实验目标是鉴定由这两种类型的光亲和配体标记的特定氨基酸残基。