title: Characterisation of the genes involved in the biosynthesis and attachment of the aminodeoxysugar D-forosamine in the auricin gene cluster of Streptomyces aureofaciens CCM3239.
abstract: We previously identified the aur1 gene cluster which produces the angucycline antibiotic auricin. Preliminary characterisation of auricin revealed that it is modified by a single aminodeoxysugar, D-forosamine. Here we characterise the D-forosamine-specific genes. The four close tandem genes, aur1TQSV, encoding enzymes involved in the initial steps of the deoxysugar biosynthesis, were located on a large operon with other core auricin biosynthetic genes. Deleting these genes resulted in the absence of auricin and the production of deglycosylated auricin intermediates. The two final D-forosamine biosynthetic genes, sa59, an NDP-hexose aminotransferase, and sa52, an NDP-aminohexose N-dimethyltransferase, are located in a region rather distant from the core auricin genes. A deletion analysis of these genes confirmed their role in D-forosamine biosynthesis. The Δsa59 mutant had a phenotype similar to that of the cluster deletion mutant, while the Δsa52 mutant produced an auricin with a demethylated D-forosamine. Although auricin contains a single deoxyhexose, two glycosyltransferase genes were found to participate in the attachment of D-forosamine to the auricin aglycon. An analysis of the expression of the D-forosamine biosynthesis genes revealed that the initial D-forosamine biosynthetic genes aur1TQSV are regulated together with the other auricin core genes by the aur1Ap promoter under the control of the auricin-specific activator Aur1P. The expression of the other D-forosamine genes, however, is governed by promoters differentially dependent upon the two SARP family auricin-specific activators Aur1PR3 and Aur1PR4. These promoters contain direct repeats similar to the SARP consensus sequence and are involved in the interaction with both regulators.
authors.affiliation: Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51, Bratislava, Slovak Republic.
authors.forename: Carmen
authors.initials: C
authors.lastname: Bekeova
authors.affiliation: Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51, Bratislava, Slovak Republic.
authors.forename: Alena
authors.initials: A
authors.lastname: Rehakova
authors.affiliation: Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51, Bratislava, Slovak Republic.
authors.forename: Lubomira
authors.initials: L
authors.lastname: Feckova
authors.affiliation: Institute of Chemistry, Slovak Academy of Sciences, 845 38, Bratislava, Slovak Republic.
authors.forename: Silvia
authors.initials: S
authors.lastname: Vlckova
authors.affiliation: Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51, Bratislava, Slovak Republic.
authors.forename: Renata
authors.initials: R
authors.lastname: Novakova
authors.affiliation: Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51, Bratislava, Slovak Republic.
authors.forename: Erik
authors.initials: E
authors.lastname: Mingyar
authors.affiliation: Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51, Bratislava, Slovak Republic. jan.kormanec@savba.sk.
authors.forename: Jan
authors.initials: J
authors.lastname: Kormanec
mesh_terms: D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006595:Hexosamines / Q000096:biosynthesis*; D018942:Macrolides / Q000378:metabolism*; D005810:Multigene Family; D009876:Operon; D011401:Promoter Regions, Genetic; D064210:Secondary Metabolism / Q000235:genetics; D016415:Sequence Alignment; D013304:Streptomyces aureofaciens / Q000235:genetics* / Q000378:metabolism; D000637:Transaminases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D006595:Hexosamines; D018942:Macrolides; C505282:auricin; C012325:forosamine; D000637:Transaminases
keywords: Antibiotics; Auricin; D-Forosamine; Polyketide; Regulation; Secondary metabolite; Streptomyces