FLUORESCENCE OF P700 AND ANTENNA CHLOROPHYLLS IN PHOTOSYSTEM-I PARTICLES THAT CONTAIN 11 CHLOROPHYLLS P700

The organization of chlorophylls in ether-extracted Photosystem I particles from spinach, which contain 11 chlorophylls per reaction center chlorophyll P700, was studied by analysis of fluorescence at temperatures between 273 and 77 K. P700 appears to emit both prompt and delayed fluorescence, with absorption and emission peaks of P700 at 696 nm and 701 nm, respectively, at 77 K. Both peaks shifted by 4 nm to the blue on warming from 77 K to 273 K. Chlorophylls with absorption peaks at 662, 670, 682, and 686 nm at 77 K transfer excitation energy to P700. Chlorophylls with an absorption peak at 676 nm emit fluorescence with a peak at 679 nm at 77 K and do not transfer excitation energy to P700.