The Supramolecular Structure of the Light-Harvesting System of Cyanobacteria and Red Algae

Abstract

Cyanobacteria including prochloron like organisms were the only procaryotes, which developed oxygenic photosynthesis. Once established the photosynthetic electron transport chain has not changed essentially during evolution to algae and higher plants. However major differences were introduced by the development of specialized light harvesting pigments, which adapt the photosynthetic apparatus of the different organisms to the changing light climates, especially to changes in light quantity and quality (Anderson, 1986). These light harvesting pigments or light harvesting antennae capture light over a large range of the spectrum and transfer the excitation energy in an energetic cascade finally to the photosynthetic reaction centres where chemical events start. Thereby they increase the photosynthetic efficency of the reaction centres to fully utilize the capacity of the electron-transport chain and that of the carbon dioxide fixation system and thus allow life in ecological niches under limited and unfavourabe conditions.