The structure of the G protein heterotrimer Gi alpha 1 beta 1 gamma 2.
Wall, M.A., Coleman, D.E., Lee, E., Iniguez-Lluhi, J.A., Posner, B.A., Gilman, A.G., Sprang, S.R.(1995) Cell 83: 1047-1058
- PubMed: 8521505 
- DOI: https://doi.org/10.1016/0092-8674(95)90220-1
- Primary Citation of Related Structures:  
1GG2, 1GP2 - PubMed Abstract: 
The crystallographic structure of the G protein heterotrimer Gi alpha 1(GDP)beta 1 gamma 2 (at 2.3 A) reveals two nonoverlapping regions of contact between alpha and beta, an extended interface between beta and nearly all of gamma, and limited interaction of alpha with gamma. The major alpha/beta interface covers switch II of alpha, and GTP-induced rearrangement of switch II causes subunit dissociation during signaling. Alterations in GDP binding in the heterotrimer (compared with alpha-GDP) explain stabilization of the inactive conformation of alpha by beta gamma. Repeated WD motifs in beta form a circularized sevenfold beta propeller. The conserved cores of these motifs are a scaffold for display of their more variable linkers on the exterior face of each propeller blade.
Organizational Affiliation: 
Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235, USA.