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Crystal structure of G alpha 12 in complex with GDP, Mg2+ and AlF4-
Structural highlights
FunctionGNA12_MOUSE Guanine nucleotide-binding proteins (G proteins) are involved as modulators or transducers in various transmembrane signaling systems. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe oncogenic G(12/13) subfamily of heterotrimeric G proteins transduces extracellular signals that regulate the actin cytoskeleton, cell cycle progression, and gene transcription. Previously, structural analyses of fully functional G alpha(12/13) subunits have been hindered by insufficient amounts of homogeneous, functional protein. Herein, we report that substitution of the N-terminal helix of G alpha(i1) for the corresponding region of G alpha12 or G alpha13 generated soluble chimeric subunits (G alpha(i/12) and G alpha(i/13)) that could be purified in sufficient amounts for crystallographic studies. Each chimera bound guanine nucleotides, G betagamma subunits, and effector proteins and exhibited GAP responses to p115RhoGEF and leukemia-associated RhoGEF. Like their wild-type counterparts, G alpha(i/13), but not G alpha(i/12), stimulated the activity of p115RhoGEF. Crystal structures of the G alpha(i/12) x GDP x AlF4(-) and G alpha(i/13) x GDP complexes were determined using diffraction data extending to 2.9 and 2.0 A, respectively. These structures reveal not only the native structural features of G alpha12 and G alpha13 subunits, which are expected to be important for their interactions with GPCRs and effectors such as G alpha-regulated RhoGEFs, but also novel conformational changes that are likely coupled to GTP hydrolysis in the G alpha(12/13) class of heterotrimeric G proteins. A new approach to producing functional G alpha subunits yields the activated and deactivated structures of G alpha(12/13) proteins.,Kreutz B, Yau DM, Nance MR, Tanabe S, Tesmer JJ, Kozasa T Biochemistry. 2006 Jan 10;45(1):167-74. PMID:16388592[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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