title: Chlorophyll modifications and their spectral extension in oxygenic photosynthesis.
abstract: Chlorophylls are magnesium-tetrapyrrole molecules that play essential roles in photosynthesis. All chlorophylls have similar five-membered ring structures, with variations in the side chains and/or reduction states. Formyl group substitutions on the side chains of chlorophyll a result in the different absorption properties of chlorophyll b, chlorophyll d, and chlorophyll f. These formyl substitution derivatives exhibit different spectral shifts according to the formyl substitution position. Not only does the presence of various types of chlorophylls allow the photosynthetic organism to harvest sunlight at different wavelengths to enhance light energy input, but the pigment composition of oxygenic photosynthetic organisms also reflects the spectral properties on the surface of the Earth. Two major environmental influencing factors are light and oxygen levels, which may play central roles in the regulatory pathways leading to the different chlorophylls. I review the biochemical processes of chlorophyll biosynthesis and their regulatory mechanisms.
authors.affiliation: School of Biological Sciences, University of Sydney, Sydney, New South Wales 2006, Australia; email: min.chen@sydney.edu.au.
authors.forename: Min
authors.initials: M
authors.lastname: Chen
mesh_terms: D019729:Carbon-Oxygen Ligases / Q000737:chemistry; D002734:Chlorophyll / Q000031:analogs & derivatives / Q000737:chemistry*; D000077194:Chlorophyll A; D008027:Light; D008190:Lyases / Q000737:chemistry; D008274:Magnesium / Q000737:chemistry; D010100:Oxygen / Q000737:chemistry*; D010788:Photosynthesis; D018521:Plant Physiological Phenomena; D011524:Protoporphyrins / Q000737:chemistry
chemical_list: D011524:Protoporphyrins; C583352:chlorophyll f; D002734:Chlorophyll; C037184:chlorophyll b; C107509:chlorophyll d; D008190:Lyases; C086788:magnesium chelatase; D019729:Carbon-Oxygen Ligases; C026901:chlorophyll synthetase; D008274:Magnesium; D010100:Oxygen; D000077194:Chlorophyll A
keywords: chlorophyll biosynthesis; evolution of chlorophylls; formyl group substitution; light and oxygen; redshifted chlorophylls; spectral extension