| Structural highlights
4a4m is a 2 chain structure with sequence from Bovin. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
| | Ligands: | , , , , |
| NonStd Res: | |
| Related: | 1ov0, 1n3m, 2i37, 1bok, 2i36, 1edx, 2j4y, 1vqx, 1ln6, 1jfp, 1ov1, 1f88, 1boj, 1nzs, 1eds, 2x72, 1u19, 1fdf, 1edw, 1hzx, 2i35, 1l9h, 1gzm, 1edv |
| Resources: | FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT |
Function
[OPSD_BOVIN] Photoreceptor required for image-forming vision at low light intensity. Required for photoreceptor cell viability after birth. Light-induced isomerization of 11-cis to all-trans retinal triggers a conformational change leading to G-protein activation and release of all-trans retinal (By similarity).[1] [2] [GNAT3_BOVIN] Guanine nucleotide-binding protein (G protein) alpha subunit playing a prominent role in bitter and sweet taste transduction as well as in umami (monosodium glutamate, monopotassium glutamate, and inosine monophosphate) taste transduction.
Publication Abstract from PubMed
G protein-coupled receptors (GPCR) are seven transmembrane helix proteins that couple binding of extracellular ligands to conformational changes and activation of intracellular G proteins, GPCR kinases, and arrestins. Constitutively active mutants are ubiquitously found among GPCRs and increase the inherent basal activity of the receptor, which often correlates with a pathological outcome. Here, we have used the M257Y(6.40) constitutively active mutant of the photoreceptor rhodopsin in combination with the specific binding of a C-terminal fragment from the G protein alpha subunit (GalphaCT) to trap a light activated state for crystallization. The structure of the M257Y/GalphaCT complex contains the agonist all-trans-retinal covalently bound to the native binding pocket and resembles the G protein binding metarhodopsin-II conformation obtained by the natural activation mechanism; i.e., illumination of the prebound chromophore 11-cis-retinal. The structure further suggests a molecular basis for the constitutive activity of 6.40 substitutions and the strong effect of the introduced tyrosine based on specific interactions with Y223(5.58) in helix 5, Y306(7.53) of the NPxxY motif and R135(3.50) of the E(D)RY motif, highly conserved residues of the G protein binding site.
Stabilized G protein binding site in the structure of constitutively active metarhodopsin-II.,Deupi X, Edwards P, Singhal A, Nickle B, Oprian D, Schertler G, Standfuss J Proc Natl Acad Sci U S A. 2012 Jan 3;109(1):119-24. Epub 2011 Dec 23. PMID:22198838[3]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Nakamichi H, Okada T. Local peptide movement in the photoreaction intermediate of rhodopsin. Proc Natl Acad Sci U S A. 2006 Aug 22;103(34):12729-34. Epub 2006 Aug 14. PMID:16908857
- ↑ Salom D, Lodowski DT, Stenkamp RE, Le Trong I, Golczak M, Jastrzebska B, Harris T, Ballesteros JA, Palczewski K. Crystal structure of a photoactivated deprotonated intermediate of rhodopsin. Proc Natl Acad Sci U S A. 2006 Oct 31;103(44):16123-8. Epub 2006 Oct 23. PMID:17060607
- ↑ Deupi X, Edwards P, Singhal A, Nickle B, Oprian D, Schertler G, Standfuss J. Stabilized G protein binding site in the structure of constitutively active metarhodopsin-II. Proc Natl Acad Sci U S A. 2012 Jan 3;109(1):119-24. Epub 2011 Dec 23. PMID:22198838 doi:10.1073/pnas.1114089108
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