Primary Citation of Related Structures:   1TBG
PubMed Abstract: 
Many signalling cascades use seven-helical transmembrane receptors coupled to heterotrimeric G proteins (G alpha beta gamma) to convert extracellular signals into intracellular responses. Upon nucleotide exchange catalysed by activated receptors, heterotrimers dissociate into GTP-bound G alpha subunits and G beta gamma dimers, either of which can modulate many downstream effectors ...
Many signalling cascades use seven-helical transmembrane receptors coupled to heterotrimeric G proteins (G alpha beta gamma) to convert extracellular signals into intracellular responses. Upon nucleotide exchange catalysed by activated receptors, heterotrimers dissociate into GTP-bound G alpha subunits and G beta gamma dimers, either of which can modulate many downstream effectors. Here we use multiwavelength anomalous diffraction data to solve the crystal structure of the beta gamma dimer of the G protein transducin. The beta-subunit is primarily a seven-bladed beta-propeller that is partially encircled by an extended gamma-subunit. The beta-propeller, which contains seven structurally similar WD repeats, defines the stereochemistry of the WD repeat and the probable architecture of all WD-repeat-containing domains. The structure details interactions between G protein beta- and gamma-subunits and highlights regions implicated in effector modulation for the conserved family of G protein beta gamma dimers.
Related Citations: 
The 2.0 A Crystal Structure of a Heterotrimeric G Protein Lambright, D.G., Sondek, J., Bohm, A., Skiba, N.P., Hamm, H.E., Sigler, P.B. (1996) Nature 379: 311
Structural Determinants for Activation of the Alpha-Subunit of a Heterotrimeric G Protein Lambright, D.G., Noel, J.P., Hamm, H.E., Sigler, P.B. (1994) Nature 369: 621
Gtpase Mechanism of Gproteins from the 1.7-A Crystal Structure of Transducin Alpha-Gdp-Aif-4 Sondek, J., Lambright, D.G., Noel, J.P., Hamm, H.E., Sigler, P.B. (1994) Nature 372: 276
The 2.2 A Crystal Structure of Transducin-Alpha Complexed with GTP Gamma S Noel, J.P., Hamm, H.E., Sigler, P.B. (1993) Nature 366: 654
Organizational Affiliation: 
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06510, USA.