title: The oligomeric states of the photosystems and the light-harvesting complexes in the Chl b-less mutant.
abstract: The reversible associations between the light-harvesting complexes (LHCs) and the core complexes of PSI and PSII are essential for the photoacclimation mechanisms in higher plants. Two types of Chls, Chl a and Chl b, both function in light harvesting and are required for the biogenesis of the photosystems. Chl b-less plants have been studied to determine the function of the LHCs because the Chl b deficiency has severe effects specific to the LHCs. Previous studies have shown that the amounts of the LHCs, especially the LHCII trimer, were decreased in the mutants; however, it is still unclear whether Chl b is required for the assembly of the LHCs and for the association of the LHCs with PSI and PSII. Here, to reveal the function of Chl b in the LHCs, we investigated the oligomeric states of the LHCs, PSI and PSII in the Arabidopsis Chl b-less mutant. A two-dimensional blue native-PAGE/SDS-PAGE demonstrated that the PSI-LHCI supercomplex was fully assembled in the absence of Chl b, whereas the trimeric LHCII and PSII-LHCII supercomplexes were not detected. The PSI-NAD(P)H dehydrogenase (NDH) supercomplexes were also assembled in the mutant. Furthermore, we detected two forms of monomeric LHC proteins. The faster migrating forms, which were detected primarily in the mutant, were probably apo-LHC proteins, whereas the slower migrating forms were probably the LHC proteins that contained Chl a. These findings increase our understanding of the Chl b function in the assembly of LHCs and the association of the LHCs with PSI, PSII and NDH.
authors: Institute of Low Temperature Science, Hokkaido University, N19 W8 Kita-Ku, Sapporo, 060-0819 Japan. takabayashi@pop.lowtem.hokudai.ac.jp
authors: Atsushi
authors: A
authors: Takabayashi
authors: Katsunori
authors: K
authors: Kurihara
authors: Masayoshi
authors: M
authors: Kuwano
authors: Yasuhiro
authors: Y
authors: Kasahara
authors: Ryouichi
authors: R
authors: Tanaka
authors: Ayumi
authors: A
authors: Tanaka
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D002734:Chlorophyll / Q000378:metabolism*; D000077194:Chlorophyll A; D004591:Electrophoresis, Polyacrylamide Gel; D005453:Fluorescence; D006358:Hot Temperature; D015151:Immunoblotting; D007425:Intracellular Membranes / Q000378:metabolism; D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000378:metabolism; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D045331:Photosystem I Protein Complex / Q000737:chemistry* / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000378:metabolism; D020836:Protein Structure, Quaternary; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D040901:Proteomics; D020524:Thylakoids / Q000378:metabolism
chemical_list: D045342:Light-Harvesting Protein Complexes; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; D021122:Protein Subunits; D002734:Chlorophyll; C037184:chlorophyll b; D000077194:Chlorophyll A