title: Cloning, sequencing and function of sanA, a gene involved in nikkomycin biosynthesis of Streptomyces ansochromogenes.
abstract: Several genetically stable mutants blocked in nikkomycin biosynthesis were obtained after the slightly germinated spores of Streptomyces ansochromogenes, a nikkomycin producer, were treated with ultra violet radiation. One of the mutants is the same in morpholotical differentiation as the wild type strain and is designated as NBB19. A DNA library was constructed using plasmid pIJ702 as cloning vector, NBB19 as cloning recipient. A 6 kb DNA fragment which can genetically complement NBB19 was cloned when screening the library for antifungal activity. Sequence analysis showed that the 3 kb Bgl II -Sal I fragment contains one complete ORF (ORF1) and one partial ORF (ORF2). ORF1 is designated as sanA. sanA is 1 365 bp, encoding a protein consisting of 454 amino acid residues. Database searching indicated that sanA is homologous to the hypothetical methyltransferase in Pyrococcus horikoshii with 25% identities and 41% positives. Disruptant of sanA lost the ability to synthesize nikkomycin. It indicated that sanA is a novel gene which is essential for nikkomycin biosynthesis.
authors.affiliation: Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
authors.forename: J
authors.initials: J
authors.lastname: Jia
authors.forename: W
authors.initials: W
authors.lastname: Li
authors.forename: W
authors.initials: W
authors.lastname: Chen
authors.forename: L
authors.initials: L
authors.lastname: Nie
authors.forename: H
authors.initials: H
authors.lastname: Tan