1fqj

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Revision as of 13:02, 20 November 2007

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spinqualitylabelsall models 1fqj, resolution 2.02Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

CRYSTAL STRUCTURE OF THE HETEROTRIMERIC COMPLEX OF THE RGS DOMAIN OF RGS9, THE GAMMA SUBUNIT OF PHOSPHODIESTERASE AND THE GT/I1 CHIMERA ALPHA SUBUNIT [(RGS9)-(PDEGAMMA)-(GT/I1ALPHA)-(GDP)-(ALF4-)-(MG2+)]

Overview

A multitude of heptahelical receptors use heterotrimeric G proteins to, transduce signals to specific effector target molecules. The G protein, transducin, Gt, couples photon-activated rhodopsin with the effector, cyclic GMP phosophodiesterase (PDE) in the vertebrate phototransduction, cascade. The interactions of the Gt alpha-subunit (alpha(t)) with the, inhibitory PDE gamma-subunit (PDEgamma) are central to effector, activation, and also enhance visual recovery in cooperation with the, GTPase-activating protein regulator of G-protein signalling (RGS)-9 (refs, 1-3). Here we describe the crystal structure at 2.0 A of rod transducin, alpha x GDP x AlF4- in complex with the effector molecule PDEgamma and the, GTPase-activating protein RGS9. In addition, we present the independently, solved crystal structures of the RGS9 RGS domain both alone and in complex, with alpha(t/i1) x GDP x AlF4-. These structures reveal insights into, effector activation, synergistic GTPase acceleration, RGS9 specificity and, RGS activity. Effector binding to a nucleotide-dependent site on alpha(t), sequesters PDEgamma residues implicated in PDE inhibition, and potentiates, recruitment of RGS9 for hydrolytic transition state stabilization and, concomitant signal termination.

About this Structure

1FQJ is a Protein complex structure of sequences from Bos taurus and rattus norvegicus and Bos taurus with MG, ALF and GDP as ligands. Active as 3',5'-cyclic-nucleotide phosphodiesterase, with EC number 3.1.4.17 Full crystallographic information is available from OCA.

Reference

Structural determinants for regulation of phosphodiesterase by a G protein at 2.0 A., Slep KC, Kercher MA, He W, Cowan CW, Wensel TG, Sigler PB, Nature. 2001 Feb 22;409(6823):1071-7. PMID:11234020

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