The seven chlorophyll-protein complexes CPIa, CPI, LHCP1, LHCP2, CPa, LHCP1 and LHCP11 known in part also from the chloroplasts of higher plants were isolated from Chlorella fusca. They were characterized by their molecular weight, their absorption maxima and their ratio of chlorophyll a/chlorophyll b. The composition of the chloropyhll-protein complexes changes during the cell cycle of Chlorella fusca. The ratio of LHCP/CPI decreases at the beginning of the light period and the ratio LHCP/CPa after the 2nd hour of the light period. Both quotients increase at the 5th hour of the light period, have a maximum at the 8th hour of the light period and decrease afterwards during the second part of the cell cycle. These alterations are no reflections of chlorophyll-accumulation, but cause modifications in the organization of the thylakoids and influence the photosynthetic efficiency of Chlorella fusca. The size of the PSI- and PSII-units during the cell cycle was estimated by these changes of the LHCP/CPI- and LHCP/CPa-ratios. In addition evidence is given that the assembly of LHCP1 and LHCP2 is no simple association of the monomeric forms of LHCPI or LHCPII.
Spectral Characterization of Five Chlorophyll-Protein Complexes
