Abstract
During the donor-side photoinhibition of spinach photosystem(PS) II, the reaction center D1 protein cross-linked with the antenna chlorophyll-binding protein CP43 of PSII lacking the oxygen-evolving complex (OEC) proteins. The cross-linking did not occur upon illumination of PSII that retained the OEC33, or when OEC33-depleted PSII was reconstituted with the OEC33 prior to illumination. These results suggest that D1, CP43 and the OEC33 are located in close proximity at the lumenal side of PSII. The present data show that the spatial arrangement of D1 and CP43 at the lumenal side of PSII in spinach chloroplasts is consistent with the assignment of these proteins recently proposed on the crystal structures of PSII from cyanobacteria. Moreover, the data suggest that the binding condition and positioning of the OEC33 in the PSII from higher plants, are different from those in cyanobacteria.
