3c7l
From Proteopedia
OCA (Talk | contribs)
(New page: 200px <!-- The line below this paragraph, containing "STRUCTURE_3c7l", creates the "Structure Box" on the page. You may change the PDB parameter (which sets the PD...)
Next diff →
Revision as of 05:55, 7 May 2008
Molecular architecture of Galphao and the structural basis for RGS16-mediated deactivation
Overview
Heterotrimeric G proteins relay extracellular cues from heptahelical transmembrane receptors to downstream effector molecules. Composed of an alpha subunit with intrinsic GTPase activity and a betagamma heterodimer, the trimeric complex dissociates upon receptor-mediated nucleotide exchange on the alpha subunit, enabling each component to engage downstream effector targets for either activation or inhibition as dictated in a particular pathway. To mitigate excessive effector engagement and concomitant signal transmission, the Galpha subunit's intrinsic activation timer (the rate of GTP hydrolysis) is regulated spatially and temporally by a class of GTPase accelerating proteins (GAPs) known as the regulator of G protein signaling (RGS) family. The array of G protein-coupled receptors, Galpha subunits, RGS proteins and downstream effectors in mammalian systems is vast. Understanding the molecular determinants of specificity is critical for a comprehensive mapping of the G protein system. Here, we present the 2.9 A crystal structure of the enigmatic, neuronal G protein Galpha(o) in the GTP hydrolytic transition state, complexed with RGS16. Comparison with the 1.89 A structure of apo-RGS16, also presented here, reveals plasticity upon Galpha(o) binding, the determinants for GAP activity, and the structurally unique features of Galpha(o) that likely distinguish it physiologically from other members of the larger Galpha(i) family, affording insight to receptor, GAP and effector specificity.
About this Structure
3C7L is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
Reference
Molecular architecture of Galphao and the structural basis for RGS16-mediated deactivation., Slep KC, Kercher MA, Wieland T, Chen CK, Simon MI, Sigler PB, Proc Natl Acad Sci U S A. 2008 Apr 29;105(17):6243-8. Epub 2008 Apr 23. PMID:18434540 Page seeded by OCA on Wed May 7 08:55:07 2008
