title: Association of High Light-Inducible HliA/HliB Stress Proteins with Photosystem 1 Trimers and Monomers of the Cyanobacterium Synechocystis PCC 6803.
abstract: Hlip (high light-inducible proteins) are important for protection of the photosynthetic apparatus of cyanobacteria from light stress. However, the interaction of these proteins with chlorophyll-protein complexes of thylakoids remains unclear. The association of HliA/HliB stress proteins with photosystem 1 (PS1) complexes of the cyanobacterium Synechocystis PCC 6803 was studied to understand their function. Western blotting demonstrated that stress-induced HliA/HliB proteins are associated with PS1 trimers in wild-type cells grown under moderate light condition (40 µmol photons/m(2) per sec). The content of these proteins increased 1.7-fold after light stress (150 µmol photons/m(2) per sec) for 1 h. In the absence of PS1 trimers (ΔpsaL mutant), the HliA/HliB proteins are associated with PS1 monomers and the PS2 complex. HliA/HliB proteins are associated with PS1 monomers but not with PS1 trimers in Synechocystis PS2-deficient mutant grown at 5 µmol photons/m(2) per sec; the content of Hli proteins associated with PS1 monomers increased 1.2-fold after light stress. The HliA/HliB proteins were not detected in wild-type cells of cyanobacteria grown in glucose-supplemented medium at 5 µmol photons/m(2) per sec, but light stress induces the synthesis of stress proteins associated with PS1 trimers. Thus, for the first time, the association of HliA/HliB proteins not only with PS1 trimers, but also with PS1 monomers is shown, which suggests a universal role of these proteins in the protection of the photosynthetic apparatus from excess light.
authors.affiliation: Bach Institute of Biochemistry, Russian Academy of Sciences, Moscow, 119071, Russia. nyurina@inbi.ras.ru.
authors.forename: D V
authors.initials: DV
authors.lastname: Akulinkina
authors.forename: Yu V
authors.initials: YV
authors.lastname: Bolychevtseva
authors.forename: I V
authors.initials: IV
authors.lastname: Elanskaya
authors.forename: N V
authors.initials: NV
authors.lastname: Karapetyan
authors.forename: N P
authors.initials: NP
authors.lastname: Yurina
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D049109:Cell Proliferation / Q000528:radiation effects; D002734:Chlorophyll / Q000378:metabolism; D008027:Light; D045342:Light-Harvesting Protein Complexes / Q000378:metabolism*; D009154:Mutation; D045331:Photosystem I Protein Complex / Q000737:chemistry* / Q000378:metabolism*; D045332:Photosystem II Protein Complex / Q000235:genetics; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D012995:Solubility; D046939:Synechocystis / Q000166:cytology / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects*; D020524:Thylakoids / Q000378:metabolism / Q000528:radiation effects
chemical_list: D001426:Bacterial Proteins; D045342:Light-Harvesting Protein Complexes; D045331:Photosystem I Protein Complex; D045332:Photosystem II Protein Complex; C091582:high light-inducible protein, cyanobacteria; D002734:Chlorophyll