The phycocyanin-chlorophyll-protein complexes isolated from Chroomonas placoidea  

作　　者：Min CHEN Qin LI Yuxuan WANG Jing WANG Kun ZHANG 

机构地区：[1]Institute of Life Science,Yantai University,Yantai 264005,China

出　　处：《Journal of Oceanology and Limnology》2022年第2期690-702,共13页海洋湖沼学报（英文）

基　　金：Supported by the Natural Science Foundation of Shandong Province(No.ZR2018LD009)。

摘　　要：An active photosystem(PS)Ⅱparticle and two light-harvesting complexes,as well as their subcomplexes that have not been reported previously,were isolated from a cryptophyte Chroomonas placoidea by Triton X-100 sucrose density gradient centrifugation.The fluorescence spectra revealed that there were efficient energy couplings between phycocyanin(PC645)and chlorophyll(Chl)within both zonesⅢandⅣof the gradient,which were designated respectively as light-harvesting complex and PSⅡparticles whose size was 15-20 nm according to negative staining in electron microscopy.When the two complexes were further resolved into sub-complexes,the energy coupling was retained in the core PSⅡcomplex(named as zoneⅣ-2 of the sucrose gradient),which contained almost no outer antenna pigment Chl c.Sodium dodecyl sulfate-polyacrylamide gel electrophoresis(SDS-PAGE)showed that the PC645 components appeared in Chl-containing protein complexes were mainly the β subunit with molecular weight of 20 kDa.These results demonstrate that PC645 in this cryptophyte was structurally but preferentially combined with the light-harvesting complex and PSⅡcore.The excitation energy absorbed by PC645 could be directly transferred to Chl a(especially the long wavelength of Chl a)in the PSⅡreaction center or via the Chl a/c-protein complex.The β subunit corresponded to the terminal fl uorescence emission and might play an important role in transmitting energy from PC645 to the Chl-protein complex.The results will help in elucidating the architecture and function of the energy transfer system comprising phycobiliproteins and Chl-protein complexes in cryptophytes.

关 键 词：Chroomonas placoidea phycocyanin-chlorophyll-protein complex photosystemⅡ light-harvesting complex(LHC) phycocyanin(PC645) fluorescence spectra 

分 类 号：Q945.11[生物学—植物学]