Abstract
Plants adjust the light harvesting capacity of two photosystems (PSI and PSII) by redistributing light-harvesting complex II (LHCII). Recently, we revealed the phosphorylation of major LHCIIs, minor LHCIIs, and PSII core proteins triggered the detachment of all LHCIIs. Also, using the RNAi mutant, we showed that the lack of minor LHCII (CP29) caused a severe effect in state transitions. To investigate the importance of major LHCIIs during state transitions, we studied Chlamydomonas reinhardtii mutant, npq5. After fusing a His-tag to CP47, we isolated PSII-LHCII supercomplexes from npq5 by nickel affinity chromatography. Gel filtration showed that three different PSII complexes were existed, as in wild type. However, no significant difference in their abundance during state transitions was observed, indicating that LHCIIs were not detached from PSII. Thus this result suggests that LHCII type IV is involved in the LHCII detachment. We will report the detailed mechanism more related to major LHCIIs.
