A. Trebst et B. Depka, ROLE OF CAROTENE IN THE RAPID TURNOVER AND ASSEMBLY OF PHOTOSYSTEM-IIIN CHLAMYDOMONAS-REINHARDTII, FEBS letters, 400(3), 1997, pp. 359-362
Inhibitors of the phytoene desaturase in carotene biosynthesis were te
sted in the enhanced rapid turnover of the D1 protein of photosystem I
I in high light exposure of Chlamydomonas reinhardtii cells. After 1 h
high light on heterotrophically grown cells in the presence of norflu
razon or fluridone, photosynthesis activity in vivo and PS II activity
in vitro is lost. The D1 protein has disappeared, PS I activity is no
t affected, nor is the D2 protein. It is concluded that beta-carotene
is essential for the assembly of the D1 protein into functional photos
ystem II. It is suspected that bleaching of beta-carotene in the react
ion center of PS II by high light destabilizes the structure and trigg
ers the degradation of the D1 protein.