Fig. 4. Photoreduction of PhrB and its mutants. Absorption values at 450 nm (upper picture) were taken from UV-visible spectra measured at indicated time points upon onset of blue-light illumination. For each protein, these values were normalized against the value measured at t = 0 min. Absorption values at 580 nm (lower picture) after subtraction of the t = 0 value and normalization to the absorbance at 280 nm.
