Monomeric G protein-coupled receptor rhodopsin in solution activates its G protein transducin at the diffusion limit -- Ernst et al. 104 (26): 10859 Data Supplement - HTML Page - index.htslp -- Proceedings of the National Academy of Sciences

Ernst et al. 10.1073/pnas.0701967104.

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Fig. 6. Fluorescence changes of rhodopsin and G_t. Fluorescence (excitation: 300 nm, emission: 340 nm) of purified rhodopsin (3 nM, 0.006% DDM; lower trace) is very low and does not change significantly upon light activation of the receptor with orange light (Schott GG495 long-pass filter; arrow indicates switch-on of light). Intrinsic tryptophan fluorescence of purified G_t (4 mM, 0.006% DDM; upper trace) remains stable upon successive addition of 200 mM GTPgS and 3 nM rhodopsin (indicated by arrows), demonstrating negligible basal activity of both G_t and unbleached rhodopsin, respectively. Activation of the receptor gives rise to a rapid fluorescence increase attributable to GTPgS uptake of the G_ta subunit. Further addition of rhodopsin (3 nM; indicated by arrow) after activation of the whole G_t pool results in a minor fluorescence change. Fluorescence intensities are given in counts per second (cps).