Abstract
Nicotine biosynthesis in Nicotiana species requires an oxidative deamination of N-methylputrescine, catalyzed by N-methylputrescine oxidase (MPO). In a screen for tobacco genes that were down-regulated in a tobacco mutant with altered regulation of nicotine biosynthesis, we identified two homologous MPO cDNAs which encode diamine oxidases of a particular subclass. Tobacco MPO genes were expressed specifically in the root, and up-regulated by jasmonate treatment. Recombinant MPO protein expressed in Escherichia coli formed a homodimer and deaminated N-methylputrescine more efficiently than symmetrical diamines. These results indicate that MPO evolved from general diamine oxidases to function effectively in nicotine biosynthesis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Cloning, Molecular
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Genes, Plant
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Molecular Sequence Data
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Nicotiana / enzymology*
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Nicotiana / genetics*
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Oxidoreductases Acting on CH-NH Group Donors / chemistry
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Oxidoreductases Acting on CH-NH Group Donors / genetics*
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Oxidoreductases Acting on CH-NH Group Donors / metabolism
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Putrescine / analogs & derivatives
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Putrescine / metabolism
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Recombinant Fusion Proteins / chemistry
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Sequence Homology, Amino Acid
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Substrate Specificity
Substances
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Recombinant Fusion Proteins
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putrescine oxidase
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Oxidoreductases Acting on CH-NH Group Donors
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Putrescine
Associated data
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GENBANK/AB289456
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GENBANK/AB289457