title: Genetic and Functional Analysis of the Biosynthesis of a Non-Ribosomal Peptide Siderophore in Burkholderia xenovorans LB400.
abstract: B. xenovorans LB400 is a model bacterium for the study of the metabolism of aromatic compounds. The aim of this study was the genomic and functional characterization of a non-ribosomal peptide synthetase containing gene cluster that encodes a siderophore in B. xenovorans LB400. The mba gene cluster from strain LB400 encodes proteins involved in the biosynthesis and transport of a hydroxamate-type siderophore. Strain LB400 has a unique mba gene organization, although mba gene clusters have been observed in diverse Burkholderiales. Bioinformatic analysis revealed the presence of promoters in the mba gene cluster that strongly suggest regulation by the ferric uptake regulator protein (Fur) and by the alternative RNA polymerase extracytoplasmic function sigma factor MbaF. Reverse transcriptase PCR analyses showed the expression of iron-regulated transcriptional units mbaFGHIJKL, mbaN, mbaABCE, mbaO, mbaP and mbaD genes under iron limitation. Chrome azurol S (CAS) assay strongly suggests that strain LB400 synthesized a siderophore under iron limitation. Mass spectrometry ESI-MS and MALDI-TOF-MS analyses revealed that the siderophore is a non-ribosomal peptide, and forms an iron complex with a molecular mass of 676 Da. Based on bioinformatic prediction, CAS assay and MS analyses, we propose that the siderophore is L-Nδ-hydroxy-Nδ-formylOrn-D-β-hydroxyAsp-L-Ser-L-Nδ-hydroxy-Nδ-formylOrn-1,4-diaminobutane that is closely related to malleobactin-type siderophores reported in B. thailandensis.
authors.affiliation: Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Center for Nanotechnology and Systems Biology & Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile.
authors.forename: María José
authors.initials: MJ
authors.lastname: Vargas-Straube
authors.affiliation: Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Center for Nanotechnology and Systems Biology & Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Cámara
authors.affiliation: Centro de Biotecnología Acuícola, Departamento de Biología, Universidad de Santiago de Chile, Santiago, Chile.
authors.forename: Mario
authors.initials: M
authors.lastname: Tello
authors.affiliation: Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Center for Nanotechnology and Systems Biology & Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile.
authors.forename: Francisco
authors.initials: F
authors.lastname: Montero-Silva
authors.affiliation: Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Center for Nanotechnology and Systems Biology & Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile.
authors.forename: Franco
authors.initials: F
authors.lastname: Cárdenas
authors.affiliation: Laboratorio de Microbiología Molecular y Biotecnología Ambiental, Departamento de Química & Center for Nanotechnology and Systems Biology & Centro de Biotecnología, Universidad Técnica Federico Santa María, Valparaíso, Chile.
authors.forename: Michael
authors.initials: M
authors.lastname: Seeger
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D019117:Burkholderia / Q000235:genetics / Q000378:metabolism; D017136:Ion Transport / Q000502:physiology; D007501:Iron / Q000378:metabolism*; D005810:Multigene Family; D017262:Siderophores / Q000096:biosynthesis / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D017262:Siderophores; D007501:Iron