4A4M

Crystal structure of the light-activated constitutively active N2C, M257Y,D282C rhodopsin mutant in complex with a peptide resembling the C-terminus of the Galpha-protein subunit (GaCT)

Summary for 4A4M

• Entry DOI: 10.2210/pdb4a4m/pdb
• Related: 1BOJ 1BOK 1EDS 1EDV 1EDW 1EDX 1F88 1FDF 1GZM 1HZX 1JFP 1L9H 1LN6 1N3M 1NZS 1OV0 1OV1 1U19 1VQX 2I35 2I36 2I37 2J4Y 2X72
• Descriptor: RHODOPSIN, GUANINE NUCLEOTIDE-BINDING PROTEIN G(T) SUBUNIT ALPHA-3, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (8 entities in total)
• Functional Keywords: signaling protein, g-protein, g-protein-coupled receptors, signal tansduction, visual system, metarhodopsin-ii
• Biological source: BOS TAURUS (BOVINE); More
• Total number of polymer chains: 2
• Total formula weight: 41648.74

Authors

Deupi, X.,Edwards, P.,Singhal, A.,Nickle, B.,Oprian, D.D.,Schertler, G.F.X.,Standfuss, J. (deposition date: 2011-10-17, release date: 2012-01-25, Last modification date: 2024-10-16)

Primary citation

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.USA, 109:119-, 2012

PubMed Abstract: 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 (GαCT) to trap a light activated state for crystallization. The structure of the M257Y/GαCT 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.

PubMed: 22198838
DOI: 10.1073/PNAS.1114089108

Experimental method

X-RAY DIFFRACTION (3.3 Å)