Photobleaching behaviour of isolated Lhcb. (A) Monomeric Lhcb isolated from solubilized thylakoids of WT and lut2.1, and trimeric LHCII from WT were analyzed by following the Qy-transition absorbance decay during strong illumination. (B) Sucrose bands 2 and 3 from WT and lut2.1 were fractionated by flat bed IEF in order to purify LHCII subunits in their monomeric and trimeric form. Kinetics of Qy-transition absorbance decay were measured on isolated complexes as described in Experimental Procedures. Chlorophyll concentrations of Lhcb were set to 8 μg/ml. Samples were cooled to 10°C during measurements.