Abstract
State transitions are regulated by redox state of cytochrome b6f complex; when the complex is reduced (state-2), a part of light harvesting complex II (LHCII) migrates from PSII to PSI, forming PSI-LHCI/II supercomplex. Here we improved conditions to induce cells to state-2 more completely by illuminating plastocyanin-deficient mutant or by dark incubation of wild type in anaerobic condition in the presence of glucose/glucoseoxidase. The thylakoid membranes isolated from these cells were solubilized and fractionated by sucrose density gradient ultracentrifugation. More PSI-LHCI/II supercomplex was obtained in A-3' band. It is noted that two thirds of CP26 remained associated with the supercomplex although only a trace amount was recovered in A-3' in the previous report. This result may be derived from the fact that the cells were induced thoroughly to state-2. We will report relative abundance of PSI-LHCI and LHCII by dissociating these two complexes in the presence of NaCl.
