title: Uptake of xenosiderophores in Bacillus subtilis occurs with high affinity and enhances the folding stabilities of substrate binding proteins.
abstract: Siderophores play an essential role in a multitude of microbial iron acquisition pathways. Many bacteria use xenosiderophores as iron sources that are produced by different microbial species in their habitat. We investigated the capacity of xenosiderophore uptake in the soil bacterium Bacillus subtilis and found that it employs several substrate binding proteins with high specificities and affinities for different ferric siderophore species. Protein-ligand interaction studies revealed dissociation constants in the low nanomolar range, while the protein folding stabilities were remarkably increased by their high-affinity ligands. Complementary growth studies confirmed the specificity of xenosiderophore uptake in B. subtilis and showed that its fitness is strongly enhanced by the extensive utilization of non-endogenous siderophores.
authors.affiliation: Department of Chemistry/Biochemistry, Philipps University Marburg, Hans Meerwein Strasse 4, and Loewe-Center for Synthetic Microbiology, D-35032 Marburg, Germany. miethke@staff.uni-marburg.de
authors.forename: Marcus
authors.initials: M
authors.lastname: Miethke
authors.forename: Timo
authors.initials: T
authors.lastname: Kraushaar
authors.forename: Mohamed A
authors.initials: MA
authors.lastname: Marahiel
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001412:Bacillus subtilis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002942:Circular Dichroism; D005798:Genes, Bacterial; D007501:Iron / Q000378:metabolism; D007700:Kinetics; D008954:Models, Biological; D009154:Mutation; D017510:Protein Folding; D055550:Protein Stability; D017384:Sequence Deletion; D017262:Siderophores / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; D017262:Siderophores; D007501:Iron