Fig. 1.

(A) Transient fluorescence spectra of WT TmThyX measured at 20 °C. The feature at ∼460 nm in the 0-ps spectrum is due to Raman scattering of water. (B) Kinetics at 520 nm of WT and Y91F ThyX. The time axis is linear until 10 ps and logarithmic thereafter. Solid lines are fits with a four-parameter exponential decay; the dashed line with power law.