title: Molecular cloning of N-methylputrescine oxidase from tobacco.
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.
authors.affiliation: Nara Institute of Science and Technology, Graduate School of Biological Sciences, 8916-5 Takayama, Ikoma, Nara, 630-0192, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Katoh
authors.forename: Tsubasa
authors.initials: T
authors.lastname: Shoji
authors.forename: Takashi
authors.initials: T
authors.lastname: Hashimoto
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D017343:Genes, Plant; D008969:Molecular Sequence Data; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D011700:Putrescine / Q000031:analogs & derivatives / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D014026:Nicotiana / Q000201:enzymology* / Q000235:genetics*
chemical_list: D011993:Recombinant Fusion Proteins; C022488:putrescine oxidase; D000587:Oxidoreductases Acting on CH-NH Group Donors; D011700:Putrescine