Unique Carotenoids in the Terrestrial Cyanobacterium Nostoc commune NIES-24: 2-Hydroxymyxol 2′-Fucoside, Nostoxanthin and Canthaxanthin (original) (raw)

2009, Current Microbiology

Cyanobacteria produce some carotenoids. We identified the molecular structures, including the stereochemistry, of all the carotenoids in the terrestrial cyanobacterium, Nostoc commune NIES-24 (IAM M-13). The major carotenoid was b-carotene. Its hydroxyl derivatives were (3R)-b-cryptoxanthin, (3R,3 0 R)-zeaxanthin, (2R,3R, 3 0 R)-caloxanthin, and (2R,3R,2 0 R,3 0 R)-nostoxanthin, and its keto derivatives were echinenone and canthaxanthin. The unique myxol glycosides were (3R,2 0 S)-myxol 2 0 -fucoside and (2R,3R,2 0 S)-2-hydroxymyxol 2 0 -fucoside. This is only the second species found to contain 2-hydroxymyxol. We propose possible carotenogenesis pathways based on our identification of the carotenoids: the hydroxyl pathway produced nostoxanthin via zeaxanthin from b-carotene, the keto pathway produced canthaxanthin from b-carotene, and the myxol pathway produced 2-hydroxymyxol 2 0 -fucoside via myxol 2 0 -fucoside. This cyanobacterium was found to contain many kinds of carotenoids and also displayed many carotenogenesis pathways, while other cyanobacteria lack some carotenoids and a part of carotenogenesis pathways compared with this cyanobacterium.