Identification of a gene cluster for antibacterial polyketide-derived antibiotic biosynthesis in the nystatin producer Streptomyces noursei ATCC 11455.
Streptomyces noursei ATCC 11455 produces the antifungal polyene antibiotic nystatin containing the deoxysugar moiety mycosamine. Part of the deoxythymidyl diphosphate (TDP)-glucose dehydratase gene (gdhA) known to be involved in deoxysugar biosynthesis was amplified by PCR from genomic DNA of S. noursei ATCC 11455. A gene library for S. noursei was made and screened with the gdhA probe. Several overlapping phage clones covering about 30 kb of the S. noursei genome were physically mapped. A partial DNA sequencing analysis of this region resulted in the identification of several putative genes typical of macrolide antibiotic biosynthetic gene clusters. A gene-transfer system for 5. noursei has been established, and gene deletion or disruption experiments within the putative biosynthetic gene cluster were performed. All of the knock-out mutants retained the ability to produce nystatin, suggesting that the identified gene cluster is not involved in biosynthesis of this antibiotic. Culture extracts from the wild-type strain and three knock-out mutants were analysed by TLC followed by a bioassay against Micrococcus luteus. Two antibacterial compounds were found to be synthesized by the wild-type strain while only one was produced by the mutants. This provided evidence for the involvement of the identified gene cluster in the biosynthesis of a presumably novel antibacterial macrolide antibiotic in S. noursei.
Zotchev
Sergey
S
UNIGEN Center for Molecular Biology and Department of Biotechnology, NTNU,N-7489 Trondheim, Norway1.
Haugan
Kare
K
Nord-Trondelag College, Dept of Engineering,N-7600 Levanger, Norway2.
Sekurova
Olga
O
UNIGEN Center for Molecular Biology and Department of Biotechnology, NTNU,N-7489 Trondheim, Norway1.
Sletta
Havard
H
SINTEF Applied Chemistry, SINTEF, N-7034 Trondheim, Norway3.
Ellingsen
Trond E
TE
SINTEF Applied Chemistry, SINTEF, N-7034 Trondheim, Norway3.
Valla
Svein
S
UNIGEN Center for Molecular Biology and Department of Biotechnology, NTNU,N-7489 Trondheim, Norway1.
D000900:Anti-Bacterial Agents / Q000096:biosynthesis*; D017353:Gene Deletion; D018014:Gene Transfer Techniques; D005798:Genes, Bacterial; D006836:Hydro-Lyases; D008969:Molecular Sequence Data; D005810:Multigene Family; D009761:Nystatin / Q000096:biosynthesis*; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D013302:Streptomyces / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
D000900:Anti-Bacterial Agents; D009761:Nystatin; D006836:Hydro-Lyases; C022771:dTDPglucose 4,6-dehydratase