RIKEN researchers discover where photosynthesis occurs in cyanobacteria
In Germany, RIKEN researchers have found out how light energy harvested by pigments besides chlorophyll is transferred to the molecular site where photosynthesis occurs in cyanobacteria. Green is the color that most people associate with plants, microalgae life and natural environments. That’s because most plants and microalgae use the green pigment chlorophyll to absorb sunlight. This absorbed visible light is converted into chemical energy, which plants use to power the process of photosynthesis.
Some microalgae such as cyanobacteria and red algae contain other pigments that complement chlorophyll by catching wavelengths that chlorophyll doesn’t absorb very well. Chlorophyll is contained in a molecular structure known as photosystems I and II, which in turn is located in the thylakoid membrane of chloroplasts. Photosystem II absorbs solar energy, converts it into chemical energy, and splits water molecules to produce molecular oxygen.
In contrast, supplementary pigments are located in neighboring molecular structures called phycobilisomes (Fig. 1), which specialize only in energy capture. The captured energy then has to be transferred to photosystem II for use in photosynthesis. But no one has yet discovered how this energy transfer occurs. While it is possible to determine the molecular structures of photosystem II and phycobilisomes separately, it has been impossible until now to determine their structures while they are connected to each other. Now researchers have found a way to isolate the phycobilisome–photosystem II megacomplex while preserving the interaction between them.
Category: Research
