Abstract
G-protein-coupled receptors (GPCRs) are seven transmembrane helix (TM) proteins that transduce signals into living cells by binding extracellular ligands and coupling to intracellular heterotrimeric G proteins (Gαβγ)1. The photoreceptor rhodopsin couples to transducin and bears its ligand 11-cis-retinal covalently bound via a protonated Schiff base to the opsin apoprotein2. Absorption of a photon causes retinal cis/trans isomerization and generates the agonist all-trans-retinal in situ. After early photoproducts, the active G-protein-binding intermediate metarhodopsin II (Meta II) is formed, in which the retinal Schiff base is still intact but deprotonated. Dissociation of the proton from the Schiff base breaks a major constraint in the protein and enables further activating steps, including an outward tilt of TM6 and formation of a large cytoplasmic crevice for uptake of the interacting C terminus of the Gα subunit3,4,5. Owing to Schiff base hydrolysis, Meta II is short-lived and notoriously difficult to crystallize. We therefore soaked opsin crystals with all-trans-retinal to form Meta II, presuming that the crystal’s high concentration of opsin in an active conformation (Ops*)6,7 may facilitate all-trans-retinal uptake and Schiff base formation. Here we present the 3.0 Å and 2.85 Å crystal structures, respectively, of Meta II alone or in complex with an 11-amino-acid C-terminal fragment derived from Gα (GαCT2). GαCT2 binds in a large crevice at the cytoplasmic side, akin to the binding of a similar Gα-derived peptide to Ops* (ref. 7). In the Meta II structures, the electron density from the retinal ligand seamlessly continues into the Lys 296 side chain, reflecting proper formation of the Schiff base linkage. The retinal is in a relaxed conformation and almost undistorted compared with pure crystalline all-trans-retinal. By comparison with early photoproducts we propose how retinal translocation and rotation induce the gross conformational changes characteristic for Meta II. The structures can now serve as models for the large GPCR family.
This is a preview of subscription content, access via your institution
Access options
Subscribe to this journal
Receive 51 print issues and online access
$199.00 per year
only $3.90 per issue
Buy this article
- Purchase on SpringerLink
- Instant access to full article PDF
Prices may be subject to local taxes which are calculated during checkout
Similar content being viewed by others
References
Rosenbaum, D. M., Rasmussen, S. G. & Kobilka, B. K. The structure and function of G-protein-coupled receptors. Nature 459, 356–363 (2009)
Palczewski, K. G protein-coupled receptor rhodopsin. Annu. Rev. Biochem. 75, 743–767 (2006)
Altenbach, C., Kusnetzow, A. K., Ernst, O. P., Hofmann, K. P. & Hubbell, W. L. High-resolution distance mapping in rhodopsin reveals the pattern of helix movement due to activation. Proc. Natl Acad. Sci. USA 105, 7439–7444 (2008)
Hofmann, K. P. et al. A G protein-coupled receptor at work: the rhodopsin model. Trends Biochem. Sci. 34, 540–552 (2009)
Choe, H.-W., Park, J. H., Kim, Y. J. & Ernst, O. P. Transmembrane signaling by GPCRs: insight from rhodopsin and opsin structures. Neuropharmacology 60, 52–57 (2011)
Park, J. H., Scheerer, P., Hofmann, K. P., Choe, H.-W. & Ernst, O. P. Crystal structure of the ligand-free G-protein-coupled receptor opsin. Nature 454, 183–187 (2008)
Scheerer, P. et al. Crystal structure of opsin in its G-protein-interacting conformation. Nature 455, 497–502 (2008)
Palczewski, K. et al. Crystal structure of rhodopsin: a G protein-coupled receptor. Science 289, 739–745 (2000)
Okada, T. et al. The retinal conformation and its environment in rhodopsin in light of a new 2.2 Å crystal structure. J. Mol. Biol. 342, 571–583 (2004)
Li, J., Edwards, P. C., Burghammer, M., Villa, C. & Schertler, G. F. Structure of bovine rhodopsin in a trigonal crystal form. J. Mol. Biol. 343, 1409–1438 (2004)
Siebert, F. Application of FTIR spectroscopy to the investigation of dark structures and photoreactions of visual pigments. Isr. J. Chem. 35, 309–323 (1995)
Lüdeke, S. et al. The role of Glu181 in the photoactivation of rhodopsin. J. Mol. Biol. 353, 345–356 (2005)
Angel, T. E., Chance, M. R. & Palczewski, K. Conserved waters mediate structural and functional activation of family A (rhodopsin-like) G protein-coupled receptors. Proc. Natl Acad. Sci. USA 106, 8555–8560 (2009)
Angel, T. E., Gupta, S., Jastrzebska, B., Palczewski, K. & Chance, M. R. Structural waters define a functional channel mediating activation of the GPCR, rhodopsin. Proc. Natl Acad. Sci. USA 106, 14367–14372 (2009)
Hildebrand, P. W. et al. A ligand channel through the G protein coupled receptor opsin. PLoS ONE 4, e4382 (2009)
Ahuja, S. et al. Helix movement is coupled to displacement of the second extracellular loop in rhodopsin activation. Nature Struct. Mol. Biol. 16, 168–175 (2009)
Smith, S. O. Structure and activation of the visual pigment rhodopsin. Annu. Rev. Biophys. 39, 309–328 (2010)
Nakamichi, H. & Okada, T. Crystallographic analysis of primary visual photochemistry. Angew. Chem. Int. Edn Engl. 45, 4270–4273 (2006)
Nakamichi, H. & Okada, T. Local peptide movement in the photoreaction intermediate of rhodopsin. Proc. Natl Acad. Sci. USA 103, 12729–12734 (2006)
Ye, S. et al. Tracking G-protein-coupled receptor activation using genetically encoded infrared probes. Nature 464, 1386–1389 (2010)
Shi, L. et al. β2 adrenergic receptor activation. Modulation of the proline kink in transmembrane 6 by a rotamer toggle switch. J. Biol. Chem. 277, 40989–40996 (2002)
Crocker, E. et al. Location of Trp265 in metarhodopsin II: implications for the activation mechanism of the visual receptor rhodopsin. J. Mol. Biol. 357, 163–172 (2006)
Nygaard, R., Frimurer, T. M., Holst, B., Rosenkilde, M. M. & Schwartz, T. W. Ligand binding and micro-switches in 7TM receptor structures. Trends Pharmacol. Sci. 30, 249–259 (2009)
Salgado, G. F. et al. Solid-state 2H NMR structure of retinal in metarhodopsin I. J. Am. Chem. Soc. 128, 11067–11071 (2006)
Ahuja, S. et al. 6-s-cis conformation and polar binding pocket of the retinal chromophore in the photoactivated state of rhodopsin. J. Am. Chem. Soc. 131, 15160–15169 (2009)
Brown, M. F., Salgado, G. F. & Struts, A. V. Retinal dynamics during light activation of rhodopsin revealed by solid-state NMR spectroscopy. Biochim. Biophys. Acta 1798, 177–193 (2010)
Lau, P. W., Grossfield, A., Feller, S. E., Pitman, M. C. & Brown, M. F. Dynamic structure of retinylidene ligand of rhodopsin probed by molecular simulations. J. Mol. Biol. 372, 906–917 (2007)
Fujimoto, Y. et al. On the bioactive conformation of the rhodopsin chromophore: absolute sense of twist around the 6-s-cis bond. Chem. Eur. J. 7, 4198–4204 (2001)
Knierim, B., Hofmann, K. P., Gartner, W., Hubbell, W. L. & Ernst, O. P. Rhodopsin and 9-demethyl-retinal analog: effect of a partial agonist on displacement of transmembrane helix 6 in class A G protein-coupled receptors. J. Biol. Chem. 283, 4967–4974 (2008)
Ballesteros, J. A. & Weinstein, H. Integrated methods for the construction of three-dimensional models and computational probing of structure-function relations in G-protein coupled receptors. Methods Neurosci. 25, 366–428 (1995)
Herrmann, R. et al. Sequence of interactions in receptor-G protein coupling. J. Biol. Chem. 279, 24283–24290 (2004)
Kabsch, W. XDS. Acta Crystallogr. D 66, 125–132 (2010)
Collaborative Computational Project, Number 4. The CCP4 suite: programs for protein crystallography. Acta Crystallogr. D 50, 760–763 (1994)
Brünger, A. T. et al. Crystallography & NMR system: a new software suite for macromolecular structure determination. Acta Crystallogr. D 54, 905–921 (1998)
Emsley, P. & Cowtan, K. Coot: model-building tools for molecular graphics. Acta Crystallogr. D 60, 2126–2132 (2004)
Laskowski, R. A., MacArthur, M. W., Moss, D. S. & Thornton, J. M. PROCHECK: A program to check the stereochemical quality of protein structures. J. Appl. Cryst. 26, 283–291 (1993)
Hooft, R. W., Vriend, G., Sander, C. & Abola, E. E. Errors in protein structures. Nature 381, 272 (1996)
McDonald, I. K. & Thornton, J. M. Satisfying hydrogen bonding potential in proteins. J. Mol. Biol. 238, 777–793 (1994)
Wallace, A. C., Laskowski, R. A. & Thornton, J. M. LIGPLOT: A program to generate schematic diagrams of protein-ligand interactions. Protein Eng. 8, 127–134 (1995)
DeLano, W. L. The PyMOL Molecular Graphics System. (DeLano Scientific, San Carlos, California, USA, 2002)
Fahmy, K. & Sakmar, T. P. Regulation of the rhodopsin-transducin interaction by a highly conserved carboxylic acid group. Biochemistry 32, 7229–7236 (1993)
Ernst, O. P., Bieri, C., Vogel, H. & Hofmann, K. P. Intrinsic biophysical monitors of transducin activation: fluorescence, UV-visible spectroscopy, light scattering, and evanescent field techniques. Methods Enzymol. 315, 471–489 (2000)
Ernst, O. P., Gramse, V., Kolbe, M., Hofmann, K. P. & Heck, M. Monomeric G protein-coupled receptor rhodopsin in solution activates its G protein transducin at the diffusion limit. Proc. Natl Acad. Sci. USA 104, 10859–10864 (2007)
Acknowledgements
We thank J. Engelmann, C. Koch and B. Bauer for technical assistance, and F. Siebert and W. Hubbell for critically reading the manuscript. We are grateful to the European Synchrotron Radiation Facility (ESRF, Grenoble), D. von Stetten and A. Royant of the ID29S-Cryobench (ESRF, Grenoble) and U. Müller and the scientific staff of the BESSY-MX/Helmholtz Zentrum Berlin für Materialien und Energie at beamlines BL 14.1 and BL 14.2, where the data were collected, for continuous support. This work was supported by the DFG Sfb449 (to O.P.E.), Sfb740 (to O.P.E. and K.P.H.) and an Advanced Investigator ERC grant (to K.P.H.) and by the Canada Research Chairs Program (to E.F.P.). H.-W.C. gratefully acknowledges the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2010-0002738) and CBNU funds for overseas research 2009. Y.J.K. thanks the Leibniz Graduate School of Molecular Biophysics, Berlin, for a scholarship.
Author information
Authors and Affiliations
Contributions
H.-W.C., Y.J.K. and J.H.P. are joint first authors. H.-W.C., Y.J.K., J.H.P. performed preparation and crystallization of opsin/opsin−GαCT2. H.-W.C. performed the soaking experiment of both crystals. O.P.E. designed GαCT2. H.-W.C., Y.J.K., J.H.P., P.S., O.P.E. performed the data collection. Y.J.K., P.S., N.K. performed the structural analysis of Meta II, and J.H.P., P.S., E.F.P. performed the structural analysis of Meta II·GαCT2. T.M. performed the spectroscopic and biochemical analysis. H.-W.C., N.K., K.P.H., P.S., O.P.E. analysed data and H.-W.C., K.P.H., O.P.E. wrote the paper with contributions from all authors.
Corresponding authors
Ethics declarations
Competing interests
The authors declare no competing financial interests.
Supplementary information
Supplementary Information
This file contains Supplementary Figures 1-10 with legends, Supplementary Tables 1-2, a Supplementary Discussion and additional references. (PDF 8968 kb)
Rights and permissions
About this article
Cite this article
Choe, HW., Kim, Y., Park, J. et al. Crystal structure of metarhodopsin II. Nature 471, 651–655 (2011). https://doi.org/10.1038/nature09789
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1038/nature09789
This article is cited by
-
Structural basis for the allosteric modulation of rhodopsin by nanobody binding to its extracellular domain
Nature Communications (2023)
-
Gαi-derived peptide binds the µ-opioid receptor
Pharmacological Reports (2023)
-
Interdisciplinary biophysical studies of membrane proteins bacteriorhodopsin and rhodopsin
Biophysical Reviews (2023)
-
Activation and signaling mechanism revealed by GPR119-Gs complex structures
Nature Communications (2022)
-
New insights into the molecular mechanism of rhodopsin retinitis pigmentosa from the biochemical and functional characterization of G90V, Y102H and I307N mutations
Cellular and Molecular Life Sciences (2022)
Comments
By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.