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1b9x
From Proteopedia
STRUCTURAL ANALYSIS OF PHOSDUCIN AND ITS PHOSPHORYLATION-REGULATED INTERACTION WITH TRANSDUCIN
Overview
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.
About this Structure
1B9X is a Protein complex structure of sequences from Bos taurus and Rattus norvegicus. Full crystallographic information is available from OCA.
Reference
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 Page seeded by OCA on Fri May 2 11:15:32 2008
