title: Iron-regulated phenylalanyl-tRNA synthetase activity in Azotobacter vinelandii.
abstract: Azotobacter vinelandii strain UA22 was produced by pTn5luxAB mutagenesis, such that the promoterless luxAB genes were transcribed in an iron-repressible manner. Tn5luxAB was localized to a fragment of chromosomal DNA encoding the thrS, infC, rpmI, rplT, pheS and pheT genes, with Tn5 inserted in the 3'-end of pheS. The isolation of this mutation in an essential gene was possible because of polyploidy in Azotobacter, such that strain UA22 carried both wild-type and mutant alleles of pheS. Phenylalanyl-tRNA synthetase activity and PHES::luxAB reporter activity was partially repressed under iron-sufficient conditions and fully derepressed under iron-limited conditions. The ferric uptake regulator (Fur) bound to a DNA sequence immediately upstream of luxAB, within the pheS gene, but PHES::luxAB reporter activity was not affected by phenylalanine availability. This suggests there is novel regulation of pheST in A. vinelandii by iron availability.
authors.affiliation: Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada T6G 2E9. bill.page@ualberta.ca
authors.forename: William J
authors.initials: WJ
authors.lastname: Page
authors.forename: Manisha
authors.initials: M
authors.lastname: Mehrotra
authors.forename: Marleen
authors.initials: M
authors.lastname: Vande Woestyne
authors.forename: Anne E
authors.initials: AE
authors.lastname: Tindale
authors.forename: Sonya L
authors.initials: SL
authors.lastname: Kujat Choy
authors.forename: Andrea S
authors.initials: AS
authors.lastname: Macyk
authors.forename: Brenda K
authors.initials: BK
authors.lastname: Leskiw
mesh_terms: D016948:Azotobacter vinelandii / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D006579:Heterozygote; D007501:Iron / Q000494:pharmacology*; D008156:Luciferases / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D010649:Phenylalanine / Q000494:pharmacology; D010652:Phenylalanine-tRNA Ligase / Q000235:genetics* / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D012097:Repressor Proteins; C068477:ferric uptake regulating proteins, bacterial; D010649:Phenylalanine; D007501:Iron; D008156:Luciferases; D010652:Phenylalanine-tRNA Ligase