Persistent spectral hole burning in oxygen-evolving photosystem II cores from cyanobacteria and higher plants

Persistent spectral hole burning was performed on active photosystem II (PSII) cores from spinach and synechocystis 6803, each containing ∼32 chlorophyll a molecules per core. Hole-burning action spectra are presented. The data appear inconsistent with a mechanism involving non-photochemical hole burning, as has previously been observed in isolated PSII protein–pigment fragments. A photochemical hole-burning mechanism involving charge separation in P680 accounts for the features of the spectra presented.