title: Annotation of the modular polyketide synthase and nonribosomal peptide synthetase gene clusters in the genome of Streptomyces tsukubaensis NRRL18488.
abstract: The high G+C content and large genome size make the sequencing and assembly of Streptomyces genomes more difficult than for other bacteria. Many pharmaceutically important natural products are synthesized by modular polyketide synthases (PKSs) and nonribosomal peptide synthetases (NRPSs). The analysis of such gene clusters is difficult if the genome sequence is not of the highest quality, because clusters can be distributed over several contigs, and sequencing errors can introduce apparent frameshifts into the large PKS and NRPS proteins. An additional problem is that the modular nature of the clusters results in the presence of imperfect repeats, which may cause assembly errors. The genome sequence of Streptomyces tsukubaensis NRRL18488 was scanned for potential PKS and NRPS modular clusters. A phylogenetic approach was used to identify multiple contigs belonging to the same cluster. Four PKS clusters and six NRPS clusters were identified. Contigs containing cluster sequences were analyzed in detail by using the ClustScan program, which suggested the order and orientation of the contigs. The sequencing of the appropriate PCR products confirmed the ordering and allowed the correction of apparent frameshifts resulting from sequencing errors. The product chemistry of such correctly assembled clusters could also be predicted. The analysis of one PKS cluster showed that it should produce a bafilomycin-like compound, and reverse transcription (RT)-PCR was used to show that the cluster was transcribed.
authors.affiliation: Faculty of Food Technology and Biotechnology, University of Zagreb, Zagreb, Croatia.
authors.forename: Marko
authors.initials: M
authors.lastname: Blazic
authors.forename: Antonio
authors.initials: A
authors.lastname: Starcevic
authors.forename: Mohamed
authors.initials: M
authors.lastname: Lisfi
authors.forename: Damir
authors.initials: D
authors.lastname: Baranasic
authors.forename: Dusan
authors.initials: D
authors.lastname: Goranovic
authors.forename: Stefan
authors.initials: S
authors.lastname: Fujs
authors.forename: Enej
authors.initials: E
authors.lastname: Kuscer
authors.forename: Gregor
authors.initials: G
authors.lastname: Kosec
authors.forename: Hrvoje
authors.initials: H
authors.lastname: Petkovic
authors.forename: John
authors.initials: J
authors.lastname: Cullum
authors.forename: Daslav
authors.initials: D
authors.lastname: Hranueli
authors.forename: Jurica
authors.initials: J
authors.lastname: Zucko
mesh_terms: D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016680:Genome, Bacterial; D008969:Molecular Sequence Data; D005810:Multigene Family; D010453:Peptide Synthases / Q000235:genetics*; D048630:Polyketide Synthases / Q000235:genetics*; D017422:Sequence Analysis, DNA; D013302:Streptomyces / Q000201:enzymology* / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D048630:Polyketide Synthases; D010453:Peptide Synthases; C104385:non-ribosomal peptide synthase