Sporophytes From Gametophytes And The Characteristics Of The Ps ¢ò And Single Particle Analysis

The life cycle of a red alga,Porphyra yezoensis consists of two phases:sporophyte and gametophyte. PSII complexes with high oxygen evolution activiteswere purified from both sporophyte and gametophyte. The oxygen evolution activitiesof PSII complexes of gametophyte is 2269.77±152.94 μmolO2/chl(mg).h and that ofsporophyte is 2256.33±141.81 μmolO2/chl(mg).h. The isolated PSII complexes werethen stored at 4oC and -80oC.Measurement of the oxygen evolution activity werecarried out every other day. The oxygen evolution activity of PSII at 4oC is higherthan that at -80oC. But the PSII complex of gametophyte at -80oC didn't have activityafter 6 days while the PSII complex of Sporophyte at -80oC was still active .The PSIIcomplexes stored under 4oC were analysed in three ways: gel filtration;oxygenevolution activity and absorption spectrum at room tempreture.From the gel filtrationprofile, we found the evolution peaks of the protein shift to left meaning the proteinaggregated during the store. From the absorption spectrum ,it was found that the peakof chlorophyll left shifted and chlorophyll became into phaeophytin.The oxygenevolution activity of PSII from both of gametophyte and sporophyte reduced duringthe store.The subunits of PSII isolated by the SDS-PAGEwere measured and theresults showed that PSII complexes purified from gametophyte contained PSII P680chlorophyll a apoprotein CP-47 and PSII reaction center protein D2 andD1,sporophyte PSII complexes contained PSII P680 chlorophyll a apoprotein CP-47,PSII P680 chlorophyll a apoprotein CP-43 and PSII reaction center protein D2 andD1.The single particle analysis showed dimmerized structure features and the size ofthe molecule was 13nm×7.8nm.The molecular mass of the oxygen evolving PSIIcomplex was estimated to be 500kDa that corresponds to the complex of PSII fromPorphyridium cruentum and the PSII complex from gametophyte was a little differentfrom that from sporophyte.