Patent ID: 7674584

Claim:
A method for detecting binding of a test compound to a G-Protein Coupled Receptor (GPCR), said method comprising (A) the steps of: i) contacting the GPCR with the test compound; ii) contacting a Gα subunit of said GPCR, which comprises a covalently bound tag capable of binding to a first detectable group, with a GTPase resistant GTP analogue having a second detectable group; iii) binding the first detectable group to the covalently bound tag, wherein the first detectable group and the second detectable group comprise fluorescent moieties which form a fluorescence resonance energy transfer FRET pair; and iv) detecting a signal by optical means to measure the level of interaction between the first detectable group and the second detectable group; or (B) the steps of: i) contacting the GPCR with the test compound; ii) binding a first detectable group to a tag; iii) contacting a Gα subunit of said GPCR, which comprises the covalently bound tag, with a GTPase resistant GTP analogue having a second detectable group, wherein the first detectable group and the second detectable group comprise fluorescent moieties which form a fluorescence resonance energy transfer FRET pair; and iv) detecting a signal by optical means to measure the level of interaction between the first detectable group and the second detectable group; and wherein said signal results from the intramolecular interaction between the first detectable group and the second detectable group; further wherein said first detectable group comprises a binding moiety which specifically binds to the tag; and further wherein the GTPase resistant GTP analogue is a compound having a formula selected from: