Mapping allosteric connections from the receptor to the nucleotide-binding pocket of heterotrimeric G proteins.

ABSTRACT: Heterotrimeric G proteins function as molecular relays that mediate signal transduction from heptahelical receptors in the cell membrane to intracellular effector proteins. Crystallographic studies have demonstrated that guanine nucleotide exchange on the Galpha subunit causes specific conformational changes in three key "switch" regions of the protein, which regulate binding to Gbetagamma subunits, receptors, and effector proteins. In the present study, nitroxide side chains were introduced at sites within the switch I region of Galphai to explore the structure and dynamics of this region throughout the G protein cycle. EPR spectra obtained for each of the Galpha(GDP), Galpha(GDP)betagamma heterotrimer and Galpha(GTPgammaS) conformations are consistent with the local environment observed

SUBMITTER: Oldham WM 

PROVIDER: S-EPMC1876549 | biostudies-literature | 2007 May

REPOSITORIES: biostudies-literature