G protein-coupled receptors are cell-surface seven-helical membrane proteins that undergo conformational changes on activation. The mammalian photoreceptor, rhodopsin, is the best-studied member of this superfamily. Here, we provide the first evidence that activation in rhodopsin may involve differential dynamic properties of side-chain versus backbone atoms. High-resolution NMR studies of α-15N-labeled receptor revealed large backbone motions in the inactive dark state. In contrast, indole side-chain 15N groups of tryptophans showed well resolved, equally intense NMR signals, suggesting restriction to a single specific conformation.
|Number of pages
|Proceedings of the National Academy of Sciences of the United States of America
|Published - Mar 9 2004
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