Abstract
The intensity of the tryptophan fluorescence of the α subunits of guanine nucleotide-binding regulatory proteins increases when they bind guanosine 5'-O-(3-thio)triphosphate (GTYγS). The kinetics of the fluorescence enhancement and of the measured binding of [35S]GTPγS are well correlated. The addition of Mg2+ to the nucleotide-bound proteins causes a further, rapid increase in the fluorescence intensity. Similar effects result from exposure of the proteins to F- and Mg2+, and the required concentration of F- is reduced by the inclusion of Al3+. It is presumed that the more highly fluorescent state of the G protein α subunits represents their active conformation.
Original language | English (US) |
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Pages (from-to) | 752-756 |
Number of pages | 5 |
Journal | Journal of Biological Chemistry |
Volume | 262 |
Issue number | 2 |
State | Published - 1987 |
ASJC Scopus subject areas
- Biochemistry
- Molecular Biology
- Cell Biology