title: Structural and functional characterization of three polyketide synthase gene clusters in Bacillus amyloliquefaciens FZB 42.
abstract: Although bacterial polyketides are of considerable biomedical interest, the molecular biology of polyketide biosynthesis in Bacillus spp., one of the richest bacterial sources of bioactive natural products, remains largely unexplored. Here we assign for the first time complete polyketide synthase (PKS) gene clusters to Bacillus antibiotics. Three giant modular PKS systems of the trans-acyltransferase type were identified in Bacillus amyloliquefaciens FZB 42. One of them, pks1, is an ortholog of the pksX operon with a previously unknown function in the sequenced model strain Bacillus subtilis 168, while the pks2 and pks3 clusters are novel gene clusters. Cassette mutagenesis combined with advanced mass spectrometric techniques such as matrix-assisted laser desorption ionization-time of flight mass spectrometry and liquid chromatography-electrospray ionization mass spectrometry revealed that the pks1 (bae) and pks3 (dif) gene clusters encode the biosynthesis of the polyene antibiotics bacillaene and difficidin or oxydifficidin, respectively. In addition, B. subtilis OKB105 (pheA sfp(0)), a transformant of the B. subtilis 168 derivative JH642, was shown to produce bacillaene, demonstrating that the pksX gene cluster directs the synthesis of that polyketide. The GenBank accession numbers for gene clusters pks1(bae), pks2, and pks3(dif) are AJ 634060.2, AJ 6340601.2, and AJ 6340602.2, respectively.
authors.affiliation: Institut für Biologie, AG Bakteriengenetik, Humboldt-Universität Berlin, Chausseestrasse 115, D-10115 Berlin, Germany.
authors.forename: Xiao-Hua
authors.initials: XH
authors.lastname: Chen
authors.forename: Joachim
authors.initials: J
authors.lastname: Vater
authors.forename: Jörn
authors.initials: J
authors.lastname: Piel
authors.forename: Peter
authors.initials: P
authors.lastname: Franke
authors.forename: Romy
authors.initials: R
authors.lastname: Scholz
authors.forename: Kathrin
authors.initials: K
authors.lastname: Schneider
authors.forename: Alexandra
authors.initials: A
authors.lastname: Koumoutsi
authors.forename: Gabriele
authors.initials: G
authors.lastname: Hitzeroth
authors.forename: Nicolas
authors.initials: N
authors.lastname: Grammel
authors.forename: Axel W
authors.initials: AW
authors.lastname: Strittmatter
authors.forename: Gerhard
authors.initials: G
authors.lastname: Gottschalk
authors.forename: Roderich D
authors.initials: RD
authors.lastname: Süssmuth
authors.forename: Rainer
authors.initials: R
authors.lastname: Borriss
mesh_terms: D001407:Bacillus / Q000145:classification / Q000201:enzymology / Q000235:genetics*; D001412:Bacillus subtilis / Q000201:enzymology / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D002874:Chromosome Mapping; D008969:Molecular Sequence Data; D005810:Multigene Family; D010802:Phylogeny; D010957:Plasmids; D048630:Polyketide Synthases / Q000235:genetics*; D017384:Sequence Deletion
chemical_list: D001426:Bacterial Proteins; D048630:Polyketide Synthases