Fig. 6. Room temperature fluorescence emission (excitation 440 nm) of variously treated PSI samples. (a) Free PSI (green) with a peak at 720 nm; when confined in ZIF-8 this shifts to 676 nm (blue); exposing to acidic conditions releases the PSI, whereupon the fluorescence profile returns (orange). Comparatively, (b) PSI denatured by using SDS has the characteristic emission at 680 nm of uncoupled chlorophyll, which is amplified by a further breakdown under acidic conditions.
