Measurement of two-photon excitation spectrum used to photoconvert a fluorescent protein (Kaede) by nonlinear Fourier-transform spectroscopy

摘要

We demonstrate the measurement of two-photon excitation (TPE) spectra, used not only for fluorescence but also for photoconversion in green-to-red photoconvertible Kaede, using nonlinear Fourier-transform spectroscopy. It was found that in unphotoconverted Kaede, the TPE spectrum for photoconversion is much different to that for green-fluorescence. This is similar to the difference between the one-photon excitation of photoconversion in the neutral form and that of green-fluorescence in the ionized form.