Isolation and Spectral Characterization of Photosystem II Reaction Center from Synechocystis sp. PCC 6803

Abstract

We isolated highly-purified photosystem (PS) II reaction center (RC) complexes from the cyanobacterium Synechocystis sp. PCC 6803 using a histidine tag introduced to the 47 kDa chlorophyll protein, and characterized their spectroscopic properties. Purification was carried out in a one-step procedure after isolation of PS II core complex. The polypeptide composition and pigment stoichiometry were the same as in spinach. Overall absorption and fluorescence properties were very similar to those of spinach PS II RCs. However, a clear band-shift of pheophytin a and β-carotene was observed. Reasons for these differences, and RC composition, are discussed on the basis of the three-dimensional structure of complexes.