title: Gene cloning and characterization of two NADH-dependent 3-quinuclidinone reductases from Microbacterium luteolum JCM 9174.
abstract: We used the resting-cell reaction to screen approximately 200 microorganisms for biocatalysts which reduce 3-quinuclidinone to optically pure (R)-(-)-3-quinuclidinol. Microbacterium luteolum JCM 9174 was selected as the most suitable organism. The genes encoding the protein products that reduced 3-quinuclidinone were isolated from M. luteolum JCM 9174. The bacC gene, which consists of 768 nucleotides corresponding to 255 amino acid residues and is a constituent of the bacilysin synthetic gene cluster, was amplified by PCR based on homology to known genes. The qnr gene consisted of 759 nucleotides corresponding to 252 amino acid residues. Both enzymes belong to the short-chain alcohol dehydrogenase/reductase (SDR) family. The genes were expressed in Escherichia coli as proteins which were His tagged at the N terminus, and the recombinant enzymes were purified and characterized. Both enzymes showed narrow substrate specificity and high stereoselectivity for the reduction of 3-quinuclidinone to (R)-(-)-3-quinuclidinol.
authors.affiliation: Department of Biotechnology, Faculty of Engineering, Biotechnology Research Center, Toyama Prefectural University, Imizu, Toyama, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Isotani
authors.forename: Junji
authors.initials: J
authors.lastname: Kurokawa
authors.forename: Fumiko
authors.initials: F
authors.lastname: Suzuki
authors.forename: Syunsuke
authors.initials: S
authors.lastname: Nomoto
authors.forename: Takashi
authors.initials: T
authors.lastname: Negishi
authors.forename: Michiko
authors.initials: M
authors.lastname: Matsuda
authors.forename: Nobuya
authors.initials: N
authors.lastname: Itoh
mesh_terms: D000192:Actinomycetales / Q000201:enzymology* / Q000235:genetics; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003067:Coenzymes / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D008969:Molecular Sequence Data; D009243:NAD / Q000378:metabolism*; D010088:Oxidoreductases / Q000235:genetics* / Q000378:metabolism*; D011812:Quinuclidines / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013379:Substrate Specificity
chemical_list: D003067:Coenzymes; D004269:DNA, Bacterial; D011812:Quinuclidines; D011993:Recombinant Fusion Proteins; D009243:NAD; C090998:3-quinuclidinone; C474540:3-quinuclidinol; D010088:Oxidoreductases