Relationship between O₂ evolution capacity and cytochrome b-559 high-potential form in Photosystem II particles

As previously shown for inside-out vesicles by Larsson et al. (Larsson, C., Jansson, C., Ljungberg, U.L., Åkerlund, H.E. and Anderson, B. (1984) in Advances in Photosynthesis Research, Vol. I, pp. 363-366 (Sybesma C., ed.), Martinus Nijhoff/Dr. W. Junk Publishers, Dordrecht, The Netherlands), we observed that NaCl 1 M washing of Photosystem II particles prepared by Triton X-100 treatment of spinach thylakoids induces both an inactivation of oxygen evolution and transformation of cytochrome b-559 from its high-potential to its low-potential form. A partial reactivation of water oxidation by 24 kDa polypeptide refixation is accompanied by a partial restoration of the cytochrome b-559 high-potential (HP) form. In contrast, reconstitution of water splitting by Ca²⁺ addition is not associated to a reestablishment of the cytochrome (HP) form. We conclude that cytochrome b-559 HP plays no role in water oxidation.