title: Role of sulfoquinovosyl diacylglycerol for the maintenance of photosystem II in Chlamydomonas reinhardtii.
abstract: The physiological role of sulfoquinovosyl diacylglycerol (SQDG) in photosynthesis was investigated with a SQDG defective mutant (hf-2) of Chlamydomonas reinhardtii that did not have any detectable amount of SQDG. The mutant showed a lower rate of photosystem II (PSII) activity by approximately 40% and also a lower growth rate than those of the wild-type. Results of genetical analysis of hf-2 strongly suggest that the SQDG defect and the lowered PSII activity are due to a single gene mutation. The supplementation of SQDG to hf-2 cells restored the lowered PSII activity to the same level as that of wild-type cells, and also enabled the mutant to grow even in the presence of 135 nm 3-(3,4-dichlorophenyl)-1,1-dimethylurea. Moreover, the incubation of isolated thylakoid membranes of hf-2 with SQDG raised the lowered PSII activity. Chemical modifications of SQDG impaired the recovery of PSII activity. The results suggest that SQDG is indispensable for PSII activity in Chlamydomonas by maintaining PSII complexes in their proper state.
authors: School of Life Science, Tokyo University of Pharmacy and Life Science, Horinouchi, Hachioji, Japan.
authors: Ayumi
authors: A
authors: Minoda
authors: Norihiro
authors: N
authors: Sato
authors: Hisayoshi
authors: H
authors: Nozaki
authors: Katsuhiko
authors: K
authors: Okada
authors: Haruko
authors: H
authors: Takahashi
authors: Kintake
authors: K
authors: Sonoike
authors: Mikio
authors: M
authors: Tsuzuki
mesh_terms: D000818:Animals; D016825:Chlamydomonas reinhardtii / Q000378:metabolism*; D006017:Glycolipids / Q000502:physiology*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*; D045332:Photosystem II Protein Complex
chemical_list: D006017:Glycolipids; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; C013694:sulfoquinovosyl diglyceride