2g83
From Proteopedia
|
Structure of activated G-alpha-i1 bound to a nucleotide-state-selective peptide: Minimal determinants for recognizing the active form of a G protein alpha subunit
Overview
G-proteins cycle between an inactive GDP-bound state and an active, GTP-bound state, serving as molecular switches that coordinate cellular, signaling. We recently used phage display to identify a series of peptides, that bind G alpha subunits in a nucleotide-dependent manner [Johnston, C., A., Willard, F. S., Jezyk, M. R., Fredericks, Z., Bodor, E. T., Jones, M., B., Blaesius, R., Watts, V. J., Harden, T. K., Sondek, J., Ramer, J. K., and Siderovski, D. P. (2005) Structure 13, 1069-1080]. Here we describe, the structural features and functions of KB-1753, a peptide that binds, selectively to GDP x AlF4(-)- and GTPgammaS-bound states of G alpha(i), subunits. KB-1753 blocks interaction of G alpha(transducin) with its, effector, cGMP phosphodiesterase, and inhibits transducin-mediated, activation of cGMP degradation. Additionally, KB-1753 interferes with RGS, protein binding and resultant GAP activity. A fluorescent KB-1753 variant, was found to act as a sensor for activated G alpha in vitro. The crystal, structure of KB-1753 bound to G alpha(i1) x GDP x AlF4(-) reveals binding, to a conserved hydrophobic groove between switch II and alpha3 helices, and, along with supporting biochemical data and previous structural, analyses, supports the notion that this is the site of effector, interactions for G alpha(i) subunits.
About this Structure
2G83 is a Single protein structure of sequence from Homo sapiens with ALF, MG and GDP as ligands. Full crystallographic information is available from OCA.
Reference
Minimal determinants for binding activated G alpha from the structure of a G alpha(i1)-peptide dimer., Johnston CA, Lobanova ES, Shavkunov AS, Low J, Ramer JK, Blaesius R, Fredericks Z, Willard FS, Kuhlman B, Arshavsky VY, Siderovski DP, Biochemistry. 2006 Sep 26;45(38):11390-400. PMID:16981699
Page seeded by OCA on Mon Nov 12 22:16:08 2007
