1b9x

From Proteopedia

STRUCTURAL ANALYSIS OF PHOSDUCIN AND ITS PHOSPHORYLATION-REGULATED INTERACTION WITH TRANSDUCIN

PDB ID 1b9x

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Structural highlights

1b9x is a 3 chain structure with sequence from Bos taurus and Rattus norvegicus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:	X-ray diffraction, Resolution 3Å
Ligands:
Resources:	FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

GBB1_BOVIN Guanine nucleotide-binding proteins (G proteins) are involved as a modulator or transducer in various transmembrane signaling systems. The beta and gamma chains are required for the GTPase activity, for replacement of GDP by GTP, and for G protein-effector interaction.

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Visual signal transduction is a nearly noise-free process that is exquisitely well regulated over a wide dynamic range of light intensity. A key component in dark/light adaptation is phosducin, a phosphorylatable protein that modulates the amount of transducin heterotrimer (Gt alpha beta gamma) available through sequestration of the beta gamma subunits (Gt beta gamma). The structure of the phosphophosducin/Gt beta gamma complex combined with mutational and biophysical analysis provides a stereochemical mechanism for the regulation of the phosducin-Gt beta gamma interaction. Phosphorylation of serine 73 causes an order-to-disorder transition of a 20-residue stretch, including the phosphorylation site, by disrupting a helix-capping motif. This transition disrupts phosducin's interface with Gt beta gamma, leading to the release of unencumbered Gt beta gamma, which reassociates with the membrane and Gt alpha to form a signaling-competent Gt alpha beta gamma heterotrimer.

A molecular mechanism for the phosphorylation-dependent regulation of heterotrimeric G proteins by phosducin.,Gaudet R, Savage JR, McLaughlin JN, Willardson BM, Sigler PB Mol Cell. 1999 May;3(5):649-60. PMID:10360181^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

References

↑ Gaudet R, Savage JR, McLaughlin JN, Willardson BM, Sigler PB. A molecular mechanism for the phosphorylation-dependent regulation of heterotrimeric G proteins by phosducin. Mol Cell. 1999 May;3(5):649-60. PMID:10360181