Fast oxygen‐independent degradation of the DI reaction center protein in photosystem II

Abstract

The DI reaction center protein in photosystem II is rapidly degraded during illumination of chloride-depleted or Tris-washed thylakoids. The degradation is independent of oxygen and occurs under anacrobic conditions provided that electrons can flow through the acceptor-side of photosystem II. This shows that oxygen-derived reactive species are not necessarily involved in the light-dependent damage of the DI protein. Instead the illumination of chloride-depleted or Tris-washed thylakoids induces long-lived, strongly oxidizing radicals on the donor-side of photosystems II which are suggested to be the damaging species for the DI protein