Adaptation of the Photosynthetic Antenna of Bchl d-Containing Bacteria to Low Light Intensities

Green sulfur bacteria are unique within photosynthetic microorganisms in their capacity to grow at extremely low light intensities. This ability is mainly related with the structure of their photosynthetic antenna, the chlorosomes, oblong bodies attached to the cytoplasmic membrane and tightly packed with antenna pigments. All green bacteria contain bacteriochlorophyll (BChl) c, d or e, in a mixture of several homologs. Together with antenna BChls, chlorosomes contain variable amounts of carotenoids and a BChl a baseplate, which acts as an intermediate in energy transfer [1].