To complete our studies, we substituted emerald GFP (emGFP) for YFP. Using two-photon excitation, CFP can be excited at 800–825 nm with little direct excitation of emGFP (which has two-photon ...

3) thus preventing discrimination of CFP and photobleached YFP on the basis of their emission or excitation spectra. During photobleaching FRET experiments, any increase in the CFP channel could ...