A near infrared electronic transition associated with conversion between S‐states of the photosynthetic O2‐evolving complex

摘要

>A new electronic transition is observable in O₂-evolving photosynthetic membranes of spinach enriched in Photosystem II. The transition occurs predominantly in the oxidation state created after a single flash of light (S₂ state). It oscillates in yield with a period of flashes when exposed to a train of short light flashes. Conditions which abolish O₂ evolution and remove functional manganese destroy this effect. The spectrum and absorptivity of the oscillating component are similar to those found in synthetic manganese dimers poised in the mixed-valent oxidation state Mn₂(III,IV). A similar structural unit is thus implicated for the manganese site involved in O₂ evolution.