Open AccessRole of sulfoquinovosyl diacylglycerol for the maintenance of photosystem II in Chlamydomonas reinhardtii
Author(s) -
Minoda Ayumi,
Sato Norihiro,
Nozaki Hisayoshi,
Okada Katsuhiko,
Takahashi Haruko,
Sonoike Kintake,
Tsuzuki Mikio
Publication year - 2002
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1033.2002.02896.x
Subject(s) - chlamydomonas reinhardtii , mutant , thylakoid , photosystem ii , photosynthesis , chlamydomonas , biology , diacylglycerol kinase , wild type , chemistry , biochemistry , chloroplast , biophysics , gene , enzyme , protein kinase c
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 ≈␣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 n m 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.