The structure of the G protein heterotrimer Giα1β1γ2

Mark A. Wall, David E. Coleman, Ethan Lee, Jorge A. Iñiguez-Lluhi, Bruce A. Posner, Alfred G. Gilman, Stephen R. Sprang

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1038 Scopus citations


The crystallographic structure of the G protein heterotrimer Giα1(GDP)β1γ2 (at 2.3 A) reveals two nonoverlapping regions of contact between α and β, an extended interface between β and nearly all of γ, and limited interaction of α with γ. The major α/β interface covers switch II of α, and GTP-induced rearrangement of switch II causes subunit dissociation during signaling. Alterations in GDP binding in the heterotrimer (compared with α-GDP) explain stabilization of the inactive conformation of α by βγ. Repeated WD motifs in β form a circularized sevenfold β 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.

Original languageEnglish
Pages (from-to)1047-1058
Number of pages12
Issue number6
StatePublished - Dec 15 1995


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