Myxoxanthophyll in Synechocystis sp. PCC 6803 is myxol 2'-dimethyl-fucoside, (3R,2'S)-myxol 2'-(2,4-di-O-methyl-alpha-L-fucoside), not rhamnoside.
We identified the molecular structures of the carotenoids in Synechocystis sp. PCC 6803. Myxoxanthophyll in this cyanobacterium was myxol 2'-dimethyl-fucoside, (3R,2'S)-myxol 2'-(2,4-di-O-methyl-alpha-L-fucoside). The sugar moiety of the pigment was not rhamnose but dimethylated fucose, which has not been reported in carotenoid glycosides. The other carotenoids were beta-carotene, (3R,3'R)-zeaxanthin, echinenone, (3'R)-3'-hydroxyechinenone and deoxymyxol 2'-dimethyl-fucoside, (2'S)-deoxymyxol 2'-(2,4-di-O-methyl-alpha-L-fucoside). Generally, the group of polar carotenoids in cyanobacteria is referred to as myxoxanthophyll, and the structure is considered to be myxol 2'-rhamnoside. Since the name myxoxanthophyll can not specify the sugar moiety and the identification of the sugar moiety is unfeasible in many cyanobacteria, we propose the following naming convention: when the sugar moiety is unknown, the name is myxol glycoside, when known, as in the case of rhamnose and alpha-L-fucose, they should be named myxol 2'-rhamnoside and myxol 2'-alpha-L-fucoside, respectively.
Takaichi
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Biological Laboratory, Nippon Medical School, Kawasaki, 211-0063 Japan. takaichi/biology@nms.ac.jp
Maoka
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Masamoto
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K
D015502:Absorptiometry, Photon; D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000737:chemistry*; D005643:Fucose / Q000737:chemistry / Q000378:metabolism; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D010860:Pigments, Biological / Q000737:chemistry; D012210:Rhamnose / Q000737:chemistry* / Q000378:metabolism; D013237:Stereoisomerism; D024341:Xanthophylls / Q000737:chemistry* / Q000378:metabolism; D065146:Zeaxanthins; D019207:beta Carotene / Q000031:analogs & derivatives / Q000737:chemistry
D010860:Pigments, Biological; D024341:Xanthophylls; D065146:Zeaxanthins; C455379:myxol dimethylfucoside; D019207:beta Carotene; D005643:Fucose; D012210:Rhamnose