Temporal Appearance of Chlorophyll-Protein Complexes and the N,N -Dicyclohexylcarbodiimide-Binding Coupling Factor(0)?Subunit III in Forming Thylakoid Membranes of Euglena gracilis

Abstract

Dark-grown Euglena gracilis strain Z were exposed to white light which induces chloroplast development including a massive formation of thylakoid membranes. Thylakoid membranes were isolated from greening cells at various times from 12 to 72 h following light-exposure. The temporal appearance in the membranes of the three main chlorophyll-protein complexes (CP1, CPa, LHCP) and the N,N(1)?dicyclohexylcarbodiimide (DCCD)-binding CF(0)-IH subunit of the coupling-factor ATPase was assessed. When the cells were greened on a medium containing the readily-metabolized carbon source, ethanol, LHCP was detected as early as 12 h, and both CP1 and CPa were detected in low quantity up to 36 h and then increased. CP1, CPa and LHCP were detected as green complexes on polyacrylamide gels earalier during greening when cells were greened on resting medium compared to cells greened in the presence of ethanol. Photosystem I activity was detected at 12 h, photosystem II activity at 18 to 24 h, and water-splitting and whole electron transport chain activities after 24 h. Correlations are made between the temporal appearances of these activities and of the chlorophyll-protein complexes. The DCCD- binding CF(0)-IH was detected in the membrane at 12 h and increased in amount thereafter.