Metabolism of cyclic carotenoids: a model for the alteration of this biosynthetic pathway in Capsicum annuum chromoplasts |
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Authors: | Philippe Hugueney Alfredo Badillo Hsu-Ching Chen Annelyse Klein Joseph Hirschberg Bilal Camara Marcel Kuntz |
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Affiliation: | Institut de Biologie Moléculaire des Plantes du CNRS and UniversitéLouis Pasteur, 12 rue du Général Zimmer, 67084 Strasbourg, France;Department of Genetics, The Hebrew University of Jerusalem, Jerusalem 91904, Israel |
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Abstract: | The biosynthetic pathway of cyclic carotenoid is known to be quantitatively and qualitatively different in the non-green plastids of Capsicum annuum fruits compared with chloroplasts. Here, the cloning is described of a novel cDNA from this organism, which encodes an enzyme catalyzing the cyclization of lycopene to β-carotene when expressed in Escherichia coli . The corresponding gene is constitutively expressed during fruit development. Significant amino acid sequence identity was observed between this enzyme and capsanthin/capsorubin synthase which is involved in the synthesis of the species-specific red carotenoids of C. annuum fruits. The latter enzyme was found also to possess a lycopene β-cyclase activity when expressed in E. coli . A model is proposed for the origin of the capsanthin/capsorubin synthase gene and the role of this enzyme, together with the newly cloned lycopene cyclase, in the specific re-channeling of linear carotenoids into β-cyclic carotenoids in C. annuum ripening fruits. |
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