title: A locus coding for putative non-ribosomal peptide/polyketide synthase functions is mutated in a swarming-defective Proteus mirabilis strain.
abstract: We describe a large bacterial locus that, unusually, encodes components typically required for both the non-ribosomal synthesis of peptides and also polyketide/fatty acid synthase function. Two tandem ABC transporter genes in this putative nrp (non-ribosomal peptide/polyketide) operon suggest that the principal product may be secreted. Immediately distal to the nrp operon is a gene, irpP, encoding a small peptide similar to the Bacillus ComX pheromone that in its mature, extracellular form increases expression of unlinked non-ribosomal peptide synthesis genes. Transcription of both the nrp operon and irpP was up-regulated in iron-limiting culture conditions, consistent with the presence of a putative Fur repressor-binding site 5' of irpP. The locus was isolated from Proteus mirabilis as the site of a TnphoA insertion causing impaired swarm cell differentiation and an aberrant swarming pattern. The mutation was in one of the transporter genes, but a comparable swarming defect resulted from interposon disruption of the putative nrp synthetase gene.
authors.affiliation: University of Cambridge, Department of Pathology, UK.
authors.forename: S
authors.initials: S
authors.lastname: Gaisser
authors.forename: C
authors.initials: C
authors.lastname: Hughes
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics; D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics; D001426:Bacterial Proteins; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D007501:Iron / Q000378:metabolism; D033862:Iron-Binding Proteins; D008969:Molecular Sequence Data; D009068:Movement; D009097:Multienzyme Complexes / Q000737:chemistry / Q000235:genetics*; D009154:Mutation; D016366:Open Reading Frames; D009876:Operon; D010453:Peptide Synthases / Q000737:chemistry / Q000235:genetics*; D033902:Periplasmic Binding Proteins; D011513:Proteus mirabilis / Q000201:enzymology / Q000235:genetics* / Q000502:physiology; D014158:Transcription, Genetic
chemical_list: D018528:ATP-Binding Cassette Transporters; D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D033862:Iron-Binding Proteins; D009097:Multienzyme Complexes; D033902:Periplasmic Binding Proteins; D007501:Iron; D010453:Peptide Synthases; C104385:non-ribosomal peptide synthase