Photochemistry beyond the red limit in chlorophyll f–containing photosystems

Lower-energy photons do the work, too Plants and cyanobacteria use chlorophyll-rich photosystem complexes to convert light energy into chemical energy. Some organisms have developed adaptations to take advantage of longer-wavelength photons. Nürnberget al. studied photosystem complexes from cyanobacteria grown in the presence of far-red light. The authors identified the primary donor chlorophyll as one of a few chlorophyll molecules in the far-red light–adapted enzymes that were chemically altered to shift their absorption spectrum. Kinetic measurements demonstrated that far-red light is capable of directly driving water oxidation, despite having less energy than the red light used by most photosynthetic organisms.Science , this issue p.1210