title: Identification of iron-acquisition proteins of Avibacterium paragallinarum.
abstract: When Avibacterium paragallinarum reference strain 0083 (serovar A) was grown in an iron-restricted culture medium, the expression of the 60, 68 and 93 kDa outer membrane proteins increased as compared with normal media. Sera of chickens experimentally infected with Av. paragallinarum recognized these iron-restriction induced proteins, suggesting their expression in vivo. The three outer membrane proteins were identified as transferrin receptor and iron transport proteins by mass spectroscopy and a search in sequence databases. As these proteins have been reported to be regulated by the Fur protein in many bacteria, we investigated, through molecular methods, the presence of the fur gene in Av. paragallinarum. A candidate fur gene of Av. paragallinarum was amplified by polymerase chain reaction using complementary primers to conserved regions of fur gene sequences from members of the Pasteurellaceae family. The nucleotide sequence of the cloned gene, from ATG to TAA stop codon, was 453 base pairs in length and the deduced amino acid sequence showed 94% identity with Fur sequences of Actinobacillus pleuropneumoniae and Haemophilus ducreyi. The Av. paragallinarum deduced Fur protein (17.8 kDa) amino acid sequence contains the N-terminal helix-turn-helix DNA-binding domain and the two iron-binding sites in the C-terminal end, typical of other described Fur proteins. The study of iron-restriction-induced proteins and the mechanism regulating their expression could lead to an understanding of the responses of Av. paragallinarum to survive in an iron-restricted environment on host mucosal surfaces.
authors.affiliation: Carrera de Biología, Facultad de Estudios Superiores Iztacala, Universidad Nacional Autónoma de México, Estado de México, Mexico.
authors.forename: E Negrete
authors.initials: EN
authors.lastname: Abascal
authors.forename: A Chantes
authors.initials: AC
authors.lastname: Guerra
authors.forename: A Serrano
authors.initials: AS
authors.lastname: Vázquez
authors.forename: V R
authors.initials: VR
authors.lastname: Tenorio
authors.forename: C Vázquez
authors.initials: CV
authors.lastname: Cruz
authors.forename: E
authors.initials: E
authors.lastname: Zenteno
authors.forename: G Paniagua
authors.initials: GP
authors.lastname: Contreras
authors.forename: S Vaca
authors.initials: SV
authors.lastname: Pacheco
mesh_terms: D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D015153:Blotting, Western; D003001:Cloning, Molecular; D019295:Computational Biology; D017931:DNA Primers / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D007501:Iron / Q000378:metabolism; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D015661:Pasteurellaceae / Q000235:genetics*; D011990:Receptors, Transferrin / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017385:Sequence Homology
chemical_list: D001426:Bacterial Proteins; D017931:DNA Primers; D011990:Receptors, Transferrin; D012097:Repressor Proteins; C068477:ferric uptake regulating proteins, bacterial; D007501:Iron