Figure 2.

Photochemical Properties of 2xLOV1 and 2xLOV2.

(A) Light-induced absorption changes recorded for the wild type (LOV1+2), 2xLOV1, and 2xLOV2 in response to blue light irradiation (300 μmol m⁻² s⁻¹, 470 ± 10 nm). Consecutive spectra were recorded after irradiations of 0, 10, 30, and 60 s at a protein concentration of 2.5 mg mL⁻¹. In each case, isosbestic points are indicated.

(B) Dark-recovery kinetics for wild-type (LOV1+2), 2xLOV1, and 2xLOV2 proteins. Dark-minus-light absorption difference spectra are shown monitoring recovery back to the initial dark state following photoexcitation (inset). Spectra were recorded every 30 s (LOV1+2), 5 s (2xLOV1), and 20 s (2xLOV2). Absorption changes after light excitation measured at 450 nm is shown in the main panel. Wild-type (LOV1+2) decay fits to two exponentials with half-lives of 60 and 735 s. Decay for 2xLOV1 and 2xLOV2 fit to single exponentials with half-lives of 12 and 46 s, respectively.