科研之友
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摘要
Animals utilize hundreds of distinct G protein-coupled receptor (GPCR)-type chemosensory receptors to detect a diverse array of chemical signals in their environment, including odors, pheromones, and tastants [1]. However, the molecular mechanisms by which these receptors selectively interact with their cognate ligands remain poorly understood. There is growing evidence that many chemosensory receptors exist in multimeric complexes [2-4], though little is known about the relative contributions of individual subunits to receptor functions. Here, we report that each of the two subunits in the heteromeric T1R2: T1R3 sweet taste receptor [2, 5-10] binds sweet stimuli though with distinct affinities and conformational changes. Furthermore, ligand affinities for T1R3 are drastically reduced by the introduction of a single amino acid change associated with decreased sweet taste sensitivity in behaving mice [11]. Thus, individual T1R subunits increase the receptive range of the sweet taste receptor, offering a functional mechanism for phenotypic variations in sweet taste.
- 出版日期2005-11-8
