Ultrafast Dynamics of rsCherryRev in Comparison with mCherry Reflecting Its Reversive Switchability.

Ultrafast dynamics of a red fluorescence protein mCherry and its reversibly switchable mutant rsCherryRev was studied by using a 10 fs visible pulse laser and fastscan transient absorption spectroscopy system. This mutation of mCherry for rsCherryRev has caused ultrafast relaxation with lifetimes of ∼0.3 ps and ∼3 ps much faster than the lifetime of mCherry (∼0.5 ns). The ultrashort lifetimes of rsCherryRev are considered to reflect the initial structural change of the chromophore during photoisomerization. The ultrashort duration of 10 fs laser pulse also visualizes that the C═C stretching mode intensity increases at ∼0.7 ps delay, reflecting the timing of photoisomerization in rsCherryRev.