FIGURE 4.

FRET in N-terminal constructs. A, dose-response curves for capsaicin for the N-terminally FP-labeled channels; n = 2 for CFP construct and n = 7 for eYFP construct. The data were fitted to the Hill equation, and the EC₅₀ values are given in the text. B, cotransfection of eYFP and CFP subunits yields a channel with essentially no FRET; therefore the predicted separation for the adjacent FPs is ≥10 nm (r₃).