Characterization of three forms of light-harvesting chlorophyll a/b-protein complexes of photosystem II isolated from the green alga, Dunaliella salina.
Three forms of light-harvesting chlorophyll a/b-protein complexes of photosystem II (LHC II) were isolated from the thylakoid membranes of Dunaliella salina grown under different irradiance conditions. Cells grown under a low intensity light condition (80 micromol quanta m(-2) s(-1)) contained one form of LHC II, LHC-L. Two other forms of LHC II, LHC-H1 and LHC-H2, were separated from the cells grown under a high intensity light condition (1,500 micromol quanta m(-2) s(-1)). LHC-L and LHC-H1 showed an apparent particle size of 310 kDa and contained four polypeptides of 31, 30, 29 and 28 kDa. LHC-H2, with a particle size of 110 kDa, consisted of 30 and 28 kDa polypeptides. LHC-L contained 7.5 molecules of Chl a, 3.2 of Chl b and 2.1 of lutein per polypeptide, analogous to the content in higher plants. LHC-H1, with 5.6 molecules of Chl a, 2.5 of Chl b and 1.8 of lutein per polypeptide was similar to that in the green alga Bryopsis maxima. LHC-L and LHC-H1 maintained high efficiency energy transfer from Chl b and lutein to Chl a molecules. LHC-H2 showed a high Chl a/b ratio of 7.5 and contained 3.4 molecules of Chl a, 0.5 of Chl b and 1.4 of lutein per polypeptide. Chl b and lutein could not completely transfer the excitation energy to Chl a in LHC-H2.
Department of Biomolecular Science, Faculty of Science, Toho University, Funabashi, Chiba, Japan.
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A
Nishigaki
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Ohshima
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Nakayama
D002734:Chlorophyll / Q000032:analysis*; D000077194:Chlorophyll A; D000460:Chlorophyta / Q000254:growth & development / Q000502:physiology* / Q000528:radiation effects; D002850:Chromatography, Gel; D004591:Electrophoresis, Polyacrylamide Gel; D008027:Light; D008029:Lighting; D008970:Molecular Weight; D045322:Photosynthetic Reaction Center Complex Proteins / Q000096:biosynthesis / Q000737:chemistry* / Q000302:isolation & purification; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry
D045322:Photosynthetic Reaction Center Complex Proteins; D002734:Chlorophyll; C037184:chlorophyll b; D000077194:Chlorophyll A