title: Brucella abortus tandem repeated ATP-binding proteins, BapA and BapB, homologs of haemophilus influenzae LktB, are not necessary for intracellular survival.
abstract: Brucella abortus actively secretes materials and uptakes nutrients to maintain the survival and multiplication of the bacteria in host cells. ATP-binding cassette (ABC) transporters can uptake or secrete diverse materials across the bacterial membrane, and thus, ABC transporters may be important for survival of the pathogen in the host. In the present study, the B. abortus genes encoding tandem repeated Brucella ATP-binding proteins, BapA and BapB, were identified. The deduced amino acid sequences of these two genes place BapA and BapB into group 6 containing RTX toxin transporters and cyclic beta-1,2-glucan transporters, one of 25 ABC transporter ortholog groups. One of the ortholog group 6 proteins, Haemophilus influenzae LktB, shows the highest similarity and identity with these two Brucella proteins. To test the role of these putative tandem repeated ABC transporters in Brucella pathogenesis, a bap deletion mutant was constructed and used to infect murine RAW 264.7 macrophages and mice. The number of cfu from RAW 264.7 cells and spleens of BALB/c mice infected with wild type or the bap deletion mutant was similar during the course of infection, suggesting the bap genes are not necessary to maintain the pathogenesis of B. abortus, or alternative compensatory mechanisms may exist to permit the intracellular survival of B. abortus in vitro and in vivo. This is the first molecular approach to investigate the role of putative ABC transporters classified into ortholog group 6 in Brucella pathogenesis.
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Department of Animal Health and Biomedical Sciences, University of Wisconsin, 1656 Linden Drive, Madison, WI 53706, USA. jko@ahabs.wisc.edu
authors.forename: J
authors.initials: J
authors.lastname: Ko
authors.forename: G A
authors.initials: GA
authors.lastname: Splitter
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D002003:Brucella abortus / Q000737:chemistry / Q000235:genetics* / Q000472:pathogenicity; D002460:Cell Line; D005260:Female; D006193:Haemophilus influenzae / Q000235:genetics; D026901:Membrane Transport Proteins; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D017354:Point Mutation; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014774:Virulence
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; C096842:LktB protein, bacteria; D026901:Membrane Transport Proteins