title: A novel FK-506-binding-like protein that lacks peptidyl-prolyl isomerase activity is involved in intracellular infection and in vivo virulence of Burkholderia pseudomallei.
abstract: Burkholderia pseudomallei is a facultative intracellular bacterial pathogen causing melioidosis, an often fatal infectious disease that is endemic in several tropical and subtropical areas around the world. We previously described a Ptk2 cell-based plaque assay screening system of B. pseudomallei transposon mutants that led to the identification of several novel virulence determinants. Using this approach we identified a mutant with reduced plaque formation in which the BPSL0918 gene was disrupted. BPSL0918 encodes a putative FK-506-binding protein (FKBP) representing a family of proteins that typically possess peptidyl-prolyl isomerase (PPIase) activity. A B. pseudomallei ΔBPSL0918 mutant showed a severely impaired ability to resist intracellular killing and to replicate within primary macrophages. Complementation of the mutant fully restored its ability to grow intracellularly. Moreover, B. pseudomallei ΔBPSL0918 was significantly attenuated in a murine model of infection. Structural modelling confirmed a modified FKBP fold of the BPSL0918-encoded protein but unlike virulence-associated FKBPs from other pathogenic bacteria, recombinant BPSL0918 protein did not possess PPIase activity in vitro. In accordance with this observation BPSL0918 exhibits several mutations in residues that have been proposed to mediate PPIase activity in other FKBPs. To our knowledge this B. pseudomallei FKBP represents the first example of this protein family which lacks PPIase activity but is important in intracellular infection of a bacterial pathogen.
authors.affiliation: Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, UK.
authors.forename: Isobel H
authors.initials: IH
authors.lastname: Norville
authors.affiliation: Friedrich Loeffler Institute of Medical Microbiology, Ernst-Moritz-Arndt University Greifswald, Greifswald, Germany.
authors.forename: Katrin
authors.initials: K
authors.lastname: Breitbach
authors.affiliation: Friedrich Loeffler Institute of Medical Microbiology, Ernst-Moritz-Arndt University Greifswald, Greifswald, Germany.
authors.forename: Kristin
authors.initials: K
authors.lastname: Eske-Pogodda
authors.affiliation: School of Biosciences, University of Exeter, Exeter EX4 4QJ, UK.
authors.forename: Nicholas J
authors.initials: NJ
authors.lastname: Harmer
authors.affiliation: Defence Science and Technology Laboratory, Porton Down, Salisbury SP4 0JQ, UK.
authors.forename: Mitali
authors.initials: M
authors.lastname: Sarkar-Tyson
authors.affiliation: School of Biosciences, University of Exeter, Exeter EX4 4QJ, UK.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Titball
authors.affiliation: Friedrich Loeffler Institute of Medical Microbiology, Ernst-Moritz-Arndt University Greifswald, Greifswald, Germany.
authors.forename: Ivo
authors.initials: I
authors.lastname: Steinmetz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016957:Burkholderia pseudomallei / Q000187:drug effects / Q000235:genetics / Q000378:metabolism / Q000472:pathogenicity*; D004195:Disease Models, Animal; D004789:Enzyme Activation / Q000235:genetics; D005260:Female; D006367:HeLa Cells; D006801:Humans; D008554:Melioidosis / Q000382:microbiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D019696:Peptidylprolyl Isomerase / Q000378:metabolism*; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000378:metabolism; D016415:Sequence Alignment; D022021:Tacrolimus Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014774:Virulence; D047090:beta-Lactams / Q000494:pharmacology
chemical_list: D001426:Bacterial Proteins; D011994:Recombinant Proteins; D047090:beta-Lactams; D022021:Tacrolimus Binding Proteins; D019696:Peptidylprolyl Isomerase