Figure 8.

Energy transfer and dissipation by LHC-II in vitro. (A) Solubilized LHC-II trimers in detergent solution are functionally independent and re-emit absorbed light as fluorescence. (B) LHC-II crystals show similar fluorescence, although its intensity and spectral range are modified by re-absorption. Conceivably, occasional tight interaction of LHC-II trimers with one another, for example, at grain boundaries, or with contaminating free pigments can generate quenching centres, to which the energy flows through the excitonically coupled complexes. (C) Randomly compacted trimers in LHC-II aggregates generate a high density of quenching centres, resulting in reduced lifetimes and conversion of the absorbed energy into heat.