Fig. 1.
Scheme for electron transfer and cofactor organization of PSII RC. Arrows show the direction of electron transfer. Pigments located on the D1 protein are shown with a subscript D1, and those on the D2 protein are shown with a subscript D2. PD1 and PD2, the special pair; ChlD1 and ChlD2, the accessory Chl; PheD1, the primary electron acceptor, pheophytin; PheD2, pheophytin; ChlzD1 and ChlzD2, peripheral Chl; QA, the secondary electron acceptor; YZ, secondary electron donor; YD, tyrosine on the D2 protein.