Abstract
Cyanidioschyzon merolae is a thermo- and acidophilic primitive red alga. We purified the Photosystem I (PSI) complexes from C. merolae and analyzed the biochemical and spectroscopic characteristics precisely. The molecular mass of the PSI complexes was estimated as 400 kDa by Blue Native (BN)-polyacrylamide gel electrophoresis (PAGE). It was also confirmed that the PSI complexes associated light-harvesting complexes (LHC) I by the following 2nd dimensional SDS-PAGE. Until now, PsaA, PsaB, PsaC, PsaE, PsaF, and PsaL polypeptides were also determined as subunits. The PSI complexes contained 200 chlorophyll a molecules, which was larger than that of pea, and 36 zeaxanthin per P700. Violaxanthin and antheraxanthin were not detected in the PSI complexes. Only one gene coding LHC was reported in the genome of C. merolae. These results suggest that the PSI complexes from C. merolae has an antenna system different from pea.
