STRUCTURAL CONFIRMATION OF A UNIQUE CAROTENOID LACTOSIDE, P457, IN SYMBIODINIUM SP. STRAIN NBRC 104787 ISOLATED FROM A SEA ANEMONE AND ITS DISTRIBUTION IN DINOFLAGELLATES AND VARIOUS MARINE ORGANISMS 1 Takahiro Wakahama Course in Molecular Biology, Graduate School of Environmental Science, Hokkaido University, Sapporo, 060-0810, Japan Aitor Laza-Martı´nez Department of Plant Biology and Ecology, University of the Basque Country, Leioa, 48940, Spain Ahmad Iskandar Bin Haji Mohd Taha Course in Molecular Biology, Graduate School of Environmental Science, Hokkaido University, Sapporo, 060-0810, Japan Hidetoshi Okuyama 2 Laboratory of Environmental Molecular Biology, Faculty of Environmental Earth Science, Hokkaido University, Sapporo, 060-0810, Japan Kiyohito Yoshida Laboratory of Genetic Ecology, Faculty of Environmental Earth Science, Hokkaido University, Sapporo, 060-0810, Japan Kazuhiro Kogame Department of Natural History Sciences, Faculty of Science, Hokkaido University, Sapporo, 060-0810, Japan Koichiro Awai Division of Global Research Leaders, Shizuoka University, Shizuoka, 422-8529, Japan Masanobu Kawachi Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, Tsukuba, 305-8506, Japan Takashi Maoka Research Institute for Production Development, Kyoto, 606-0805, Japan and Shinichi Takaichi Department of Biology, Nippon Medical School, Kawasaki, 211-0061, Japan The molecular structure of the carotenoid lactoside P457, (3S,5R,6R,3′S,5′R,6′S)-13′-cis-5,6- epoxy-3′ ,5′ -dihydroxy-3-( b- D-galactosyl-(1?4)- b- D- glucosyl)oxy-6′,7′-didehydro-5,6,7,8,5′,6′-hexahydro- b,b-caroten-20-al, was confirmed by spectroscopic methods using Symbiodinium sp. strain NBRC 104787 cells isolated from a sea anemone. Among various algae, cyanobacteria, land plants, and marine invertebrates, the distribution of this unique diglycosyl carotenoid was restricted to free-living peridinin-containing dinoflagellates and marine invertebrates that harbor peridinin-containing zooxanthellae. Neoxanthin appeared to be a common precursor for biosynthesis of peridinin and P457, although neoxanthin was not found in peridinin-containing dinoflagellates. Fucoxanthin- containing dinoflagellates did not possess peridinin or P457; green dinoflagellates, which contain chlorophyll a and b, did not contain peridinin, fucoxanthin, or P457; and no unicellular algae containing both peridinin and P457, other than peridinin-containing dinoflagellates, have been observed. Therefore, the biosynthetic pathways for peridinin and P457 may have been coestablished during the evolution of dinoflagellates after the host heterotrophic eukaryotic microorganism formed a symbiotic association with red alga that does not contain peridinin or P457. Key index words: carotenoid; dinoflagellates; P457; peridinin; Symbiodinium; symbiosis Abbreviations: CD, circular dichroism; FAB-MS, fast atom bombardment mass spectrometry; FD-MS, field desorption mass spectrometry; ROESY, rotat- ing frame nuclear Overhauser effect spectroscopy 1 Received 1 March 2012. Accepted 16 May 2012. 2 Author for correspondence: e-mail hoku@ees.hokudai.ac.jp. J. Phycol. 48, 1392–1402 (2012) © 2012 Phycological Society of America DOI: 10.1111/j.1529-8817.2012.01219.x 1392