title: Mycosporine-like amino acids (MAAs): chemical structure, biosynthesis and significance as UV-absorbing/screening compounds.
abstract: Continuous depletion of the stratospheric ozone layer has resulted in an increase in ultraviolet-B (UV-B; 280-315 nm) radiation on the earth's surface which inhibits photochemical and photobiological processes. However, certain photosynthetic organisms have evolved mechanisms to counteract the toxicity of ultraviolet or high photosynthetically active radiation by synthesizing the UV-absorbing/screening compounds, such as mycosporine-like amino acids (MAAs) and scytonemin besides the repair of UV-induced damage of DNA and accumulation of carotenoids and detoxifying enzymes or radical quenchers and antioxidants. Chemical structure of various MAAs, their possible biochemical routes of synthesis and role as photoprotective compounds in various organisms are discussed.
authors.affiliation: Centre of Advanced Study in Botany, Banaras Hindu University, Varanasi 221 005, India.
authors.forename: Shailendra P
authors.initials: SP
authors.lastname: Singh
authors.forename: Sunita
authors.initials: S
authors.lastname: Kumari
authors.forename: Rajesh P
authors.initials: RP
authors.lastname: Rastogi
authors.forename: Kanchan L
authors.initials: KL
authors.lastname: Singh
authors.forename: Rajeshwar P
authors.initials: RP
authors.lastname: Sinha
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D000975:Antioxidants / Q000378:metabolism; D018533:Biomass; D000458:Cyanobacteria / Q000378:metabolism; D003511:Cyclohexanols / Q000737:chemistry* / Q000494:pharmacology; D004247:DNA / Q000737:chemistry; D056890:Eukaryota / Q000378:metabolism; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D008027:Light; D008954:Models, Biological; D008956:Models, Chemical; D015394:Molecular Structure; D010100:Oxygen / Q000737:chemistry; D010788:Photosynthesis; D010839:Phytoplankton / Q000378:metabolism*; D014466:Ultraviolet Rays
chemical_list: D000596:Amino Acids; D000975:Antioxidants; D003511:Cyclohexanols; C463482:mycosporine-2-glycine; D004247:DNA; D010100:Oxygen; D005998:Glycine