2hlb
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(New page: 200px<br /> <applet load="2hlb" size="450" color="white" frame="true" align="right" spinBox="true" caption="2hlb, resolution 2.2Å" /> '''A Structural Basis f...)
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Revision as of 20:27, 12 November 2007
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A Structural Basis for Nucleotide Exchange on G-alpha-i Subunits and Receptor Coupling Specificity
Contents |
Overview
Heterotrimeric G proteins are molecular switches that relay information, intracellularly in response to various extracellular signals. How, ligand-activated G protein-coupled receptors act at a distance to exert, exchange activity on the Galpha nucleotide binding pocket is poorly, understood. Here we describe the synergistic action of two peptides: one, from the third intracellular loop of the D2 dopamine receptor (D2N), and a, second, Galpha.GDP-binding peptide (KB-752) that mimics the proposed role, of Gbetagamma in receptor-promoted nucleotide exchange. The structure of, both peptides in complex with Galpha(i1) suggests that conformational, changes in the beta3/alpha2 loop and beta6 strand act in concert for, efficient nucleotide exchange. Two key residues in the alpha4 helix were, found to define a receptor/Galpha(i) coupling specificity determinant.
Disease
Known disease associated with this structure: Dystonia, myoclonic OMIM:[126450]
About this Structure
2HLB is a Protein complex structure of sequences from Homo sapiens with SO4 and GDP as ligands. Full crystallographic information is available from OCA.
Reference
Structural basis for nucleotide exchange on Galphai subunits and receptor coupling specificity., Johnston CA, Siderovski DP, Proc Natl Acad Sci U S A. 2007 Feb 6;104(6):2001-6. Epub 2007 Jan 30. PMID:17264214
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