Chapter Four - Chlorophylls d and f: Synthesis, occurrence, light-harvesting, and pigment organization in chlorophyll-binding protein complexes.

Now is a very exciting time for those people who are interested in understanding oxygenic photosynthesis driven by longer wavelength radiation. The past two decades have seen the determination of molecular mechanisms of photosynthesis driven by long wavelengths. Apart from the characterization of additional potential of longer wavelength absorption from chlorophyll a, the two chlorophyll variants chlorophyll d and chlorophyll f were introduced with red-shifted absorption features compared to chlorophyll a and chlorophyll b, which are attributable to the position of the formyl substitutions. The maximal absorption of chlorophyll d is 697 nm, 32 nm red-shifted compared with that of chlorophyll a at 665 nm in 100% methanol; while the maximal absorption of chlorophyll f is 707 nm in methanol, red-shifted 42 nm compared with that of chlorophyll a. Chlorophyll d was reported to be widely distributed in the ecological niches with lower light intensities, but enriched by far-red wavelength light, but so far has been found only in one species of cyanobacteria, Acaryochloris marina. Chlorophyll f is co-occurring with chlorophyll a and its biosynthesis is regulated by far-red light conditions. It has been reported from various genera of cyanobacteria. [ABSTRACT FROM AUTHOR]