title: Characterization and expression of the pseudomonas putida bacterioferritin alpha subunit gene.
abstract: The root-colonizing pseudomonad Pseudomonas putida (Pp) appears to produce two subunits, alpha and beta, of the iron-binding protein, bacterioferritin. A gene encoding the alpha-bacterioferritin subunit was located adjacent to the major catalase in Pp. The deduced protein sequence of the Pp bfralpha gene had a very high identity with other alpha-subunits, possessing conserved amino acids responsible for ferroxidase activity. The gene also lacked a deduced methionine at residue 52, associated with heme binding in beta-subunits. An antibody generated toward the Escherichia coli (E. coli) multifunctional single subunit bacterioferritin recognized two proteins in the Pp extract, a 22 kDa protein likely to be a beta-subunit and, to a lesser extent, a 23 kDa band. The 23 kDa band was absent in a Pp mutant in which the bfralpha gene was disrupted. Loss of alpha-bacterioferritin stimulated production of fluorescent siderophore. Growth on media and on root surfaces was not impaired by deletion of the alpha-bacterioferritin. Transcription of bfralpha was independent of the catalase gene and was dependent on iron. The transcript levels from bfralpha decreased in iron deficiency experienced during stationary-phase or upon treatment during growth with an iron chelator.
authors.affiliation: Department of Biology, Utah State University, Logan, UT 84322-5305, USA.
authors.forename: C D
authors.initials: CD
authors.lastname: Miller
authors.forename: Y C
authors.initials: YC
authors.lastname: Kim
authors.forename: M K
authors.initials: MK
authors.lastname: Walsh
authors.forename: A J
authors.initials: AJ
authors.lastname: Anderson
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D002455:Cell Division / Q000187:drug effects / Q000235:genetics; D007887:Fabaceae / Q000382:microbiology; D005293:Ferritins / Q000235:genetics*; D015870:Gene Expression; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D007501:Iron / Q000494:pharmacology; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D016296:Mutagenesis; D018517:Plant Roots / Q000382:microbiology; D010946:Plants, Medicinal; D016958:Pseudomonas putida / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017262:Siderophores / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D001426:Bacterial Proteins; D011993:Recombinant Fusion Proteins; D017262:Siderophores; D005293:Ferritins; D007501:Iron; D008156:Luciferases