Abstract
Pigment components of electron donors P740 and P720 in PS I and PS II reaction centers, respectively, were studied by laser photolysis of thylakoid membranes of Acaryochloris marina that has Chl d as the major pigment. We measured laser-induced difference spectrum of P720 in the presence of ferricyanide. It showed negative peaks at 684 and 715 nm, but no change at 740 nm. Further addition of ascorbate induced the laser-induced absorption change of P740 together with P720. The difference spectrum of P740 was calculated. It seems to be composed of bleach of Chl d special pair at 740 nm, shifts of Chl d accessory and Chl a acceptor pigments. The P720 spectrum seems to be interpreted as the bleach of Chl d special pair at 725 nm, Chl d accessory shift and the shift of the acceptor Pheophytin a (or Chl a).
