Abstract
Diatoms possess fucoxanthin chlorophyll a/c binding proteins (FCPs) as a light harvesting apparatus. The diatom FCPs have been rather poorly understood compared to light harvesting chlorophyll a/b complexes from higher plants and green algae. Although PSI specific FCPs have been reported, there is very little knowledge with regard to FCPs associated with PSII.
Recently, we succeeded in isolation of oxygen evolving crude PSII particles (crude PSII) from a marine centric diatom, Chaetoceros gracilis (UTEX LB 2658). The crude PSII contained several FCP subunits in addition to the PSII subunits. In this study, we attempted to fractionate the FCP subunits by sucrose density gradient centrifugation after treatment of the crude PSII with Triton X-100. We obtained several FCP fractions of different polypeptide composition. Spectral properties and pigment composition will also be presented for discussion of functional organization of the FCP-based light-harvesting system for PSII in diatoms.
