Crystal Structure of Rhodopsin: A G Protein-Coupled Receptor

作者：Krzysztof Palczewski, Takashi Kumasaka, Tetsuya Hori, Craig A. Behnke, Hiroyuki Motoshima, Brian A. Fox, Isolde Le Trong, David C. Teller, Tetsuji Okada, Ronald E. Stenkamp, Masaki Yamamoto, Masashi Miyano · 发表于：Science · 年份：2000 · DOI：10.1126/science.289.5480.739 · 被引用次数：5665 · 研究领域：Photoreceptor and optogenetics research、Receptor Mechanisms and Signaling、Neuroscience and Neuropharmacology Research

Heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors (GPCRs) respond to a variety of different external stimuli and activate G proteins. GPCRs share many structural features, including a bundle of seven transmembrane alpha helices connected by six loops of varying lengths. We determined the structure of rhodopsin from diffraction data extending to 2.8 angstroms resolution. The highly organized structure in the extracellular region, including a conserved disulfide bridge, forms a basis for the arrangement of the seven-helix transmembrane motif. The ground-state chromophore, 11-cis-retinal, holds the transmembrane region of the protein in the inactive conformation. Interactions of the chromophore with a cluster of key residues determine the wavelength of the maximum absorption. Changes in these interactions among rhodopsins facilitate color discrimination. Identification of a set of residues that mediate interactions between the transmembrane helices and the cytoplasmic surface, where G-protein activation occurs, also suggests a possible structural change upon photoactivation.