title: Functional analyses of oxygenases in jadomycin biosynthesis and identification of JadH as a bifunctional oxygenase/dehydrase.
abstract: A novel angucycline metabolite, 2,3-dehydro-UWM6, was identified in a jadH mutant of Streptomyces venezuelae ISP5230. Both UWM6 and 2,3-dehydro-UWM6 could be converted to jadomycin A or B by a ketosynthase alpha (jadA) mutant of S. venezuelae. These angucycline intermediates were also converted to jadomycin A by transformant of the heterologous host Streptomyces lividans expressing the jadFGH oxygenases in vivo and by its cell-free extracts in vitro; thus the three gene products JadFGH are implicated in catalysis of the post-polyketide synthase biosynthetic reactions converting UWM6 to jadomycin aglycone. Genetic and biochemical analyses indicate that JadH possesses dehydrase activity, not previously associated with polyketide-modifying oxygenase. Since the formation of aromatic polyketides often requires multiple dehydration steps, bifunctionality of oxygenases modifying aromatic polyketides may be a general phenomenon.
authors.affiliation: State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences and Graduate School of Chinese Academy of Sciences, Beijing 100080, China.
authors.forename: Yi-Hua
authors.initials: YH
authors.lastname: Chen
authors.forename: Chen-Chen
authors.initials: CC
authors.lastname: Wang
authors.forename: Lisa
authors.initials: L
authors.lastname: Greenwell
authors.forename: Uwe
authors.initials: U
authors.lastname: Rix
authors.forename: Dirk
authors.initials: D
authors.lastname: Hoffmeister
authors.forename: Leo C
authors.initials: LC
authors.lastname: Vining
authors.forename: Jürgen
authors.initials: J
authors.lastname: Rohr
authors.forename: Ke-Qian
authors.initials: KQ
authors.lastname: Yang
mesh_terms: D000595:Amino Acid Sequence; D015139:Blotting, Southern; D002384:Catalysis; D002474:Cell-Free System; D004926:Escherichia coli / Q000378:metabolism; D005821:Genetic Techniques; D006836:Hydro-Lyases / Q000737:chemistry / Q000502:physiology*; D007546:Isoquinolines / Q000737:chemistry / Q000378:metabolism*; D008956:Models, Chemical; D008957:Models, Genetic; D008969:Molecular Sequence Data; D009154:Mutation; D010105:Oxygenases / Q000737:chemistry / Q000502:physiology*; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017422:Sequence Analysis, DNA; D013045:Species Specificity; D013053:Spectrophotometry; D013302:Streptomyces / Q000378:metabolism; D048170:Streptomyces lividans / Q000378:metabolism
chemical_list: D007546:Isoquinolines; C081750:jadomycin B; D010105:Oxygenases; D006836:Hydro-Lyases