Abstract
Compounds that include (a) keto group(s) in a molecule are ubiquitous natural components. A novel gene involved in ketocompound biosynthesis, designated crtW, was isolated from the marine bacteria Agrobacterium aurantiacum and Alcaligenes PC-1 that produce ketocarotenoids such as astaxanthin. When this gene was introduced into Escherichia coli that accumulated beta-carotene due to the Erwinia carotenogenic genes, the E. coli transformants synthesized canthaxanthin, one of ketocarotenoids, which was identified after purification by its visible, FD-MS and 1H-NMR spectral analysis. It has been demonstrated for the first time that one gene encodes an enzyme "ketolase" that catalyzes the conversion of methylene groups of a hydrocarbon beta-carotene to keto groups for synthesizing canthaxanthin via echinenone.
MeSH terms
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Alcaligenes / genetics
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Alcaligenes / metabolism*
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Amino Acid Sequence
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Bacterial Proteins / biosynthesis
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Bacterial Proteins / chemistry
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Bacterial Proteins / metabolism*
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Canthaxanthin / biosynthesis*
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Carotenoids / metabolism*
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Chromosomes, Bacterial
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Cloning, Molecular
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DNA, Bacterial / isolation & purification
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DNA, Bacterial / metabolism
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Erwinia / genetics
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Erwinia / metabolism
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Escherichia coli / metabolism
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Genes, Bacterial*
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Magnetic Resonance Spectroscopy
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Mass Spectrometry
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Molecular Sequence Data
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Oxygenases / biosynthesis
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Oxygenases / chemistry
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Oxygenases / metabolism*
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Plasmids
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Restriction Mapping
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Rhizobium / genetics
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Rhizobium / metabolism*
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Seawater
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Sequence Homology, Amino Acid
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beta Carotene
Substances
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Bacterial Proteins
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DNA, Bacterial
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beta Carotene
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Carotenoids
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Canthaxanthin
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Oxygenases
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beta-carotene ketolase