Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
Cell. 2013 Dec 5;155(6):1258-69. doi: 10.1016/j.cell.2013.11.008. Epub 2013 Nov 27.
Molecular determinants regulating the activation of class B G-protein-coupled receptors (GPCRs) by native peptide agonists are largely unknown. We have investigated here the interaction between the corticotropin releasing factor receptor type 1 (CRF1R) and its native 40-mer peptide ligand Urocortin-I directly in mammalian cells. By incorporating unnatural amino acid photochemical and new click-chemical probes into the intact receptor expressed in the native membrane of live cells, 44 intermolecular spatial constraints have been derived for the ligand-receptor interaction. The data were analyzed in the context of the recently resolved crystal structure of CRF1R transmembrane domain and existing extracellular domain structures, yielding a complete conformational model for the peptide-receptor complex. Structural features of the receptor-ligand complex yield molecular insights on the mechanism of receptor activation and the basis for discrimination between agonist and antagonist function.
分子决定因素调节了天然肽激动剂激活 B 类 G 蛋白偶联受体（GPCR）的机制，但目前仍知之甚少。在这里，我们直接在哺乳动物细胞中研究了促肾上腺皮质释放因子受体 1（CRF1R）与其天然 40 个氨基酸肽配体 Urocortin-I 之间的相互作用。通过将非天然氨基酸光化学和新的点击化学探针整合到活细胞天然膜中表达的完整受体中，得出了 44 个配体-受体相互作用的分子空间限制。根据最近解析的 CRF1R 跨膜结构域和现有的细胞外结构域结构，对数据进行了分析，得出了肽-受体复合物的完整构象模型。该受体-配体复合物的结构特征为受体激活机制以及区分激动剂和拮抗剂功能的基础提供了分子见解。
