Figure 2. Photobleaching difference spectra for purified wild-type and mutant green opsins

Spectra were measured both prior to and following bleaching with light at 495 nm wavelength and differences were calculated. The difference spectra show that both the wild type (Grn) and mutant opsins (P307L) form visual pigments with absorption maxima at 530 nm. The scales of the type graphs are different and demonstrate markedly diminished absorption for the mutant pigment compared to the wild-type.