title: A Novel, Molybdenum-Containing Methionine Sulfoxide Reductase Supports Survival ofHaemophilus influenzaein anIn vivoModel of Infection.
abstract: Haemophilus influenzaeis a host adapted human mucosal pathogen involved in a variety of acute and chronic respiratory tract infections, including chronic obstructive pulmonary disease and asthma, all of which rely on its ability to efficiently establish continuing interactions with the host. Here we report the characterization of a novel molybdenum enzyme, TorZ/MtsZ that supports interactions ofH. influenzaewith host cells during growth in oxygen-limited environments. Strains lacking TorZ/MtsZ showed a reduced ability to survive in contact with epithelial cells as shown by immunofluorescence microscopy and adherence/invasion assays. This included a reduction in the ability of the strain to invade human epithelial cells, a trait that could be linked to the persistence ofH. influenzae. The observation that in a murine model ofH. influenzaeinfection, strains lacking TorZ/MtsZ were almost undetectable after 72 h of infection, while ∼3.6 × 103CFU/mL of the wild type strain were measured under the same conditions is consistent with this view. To understand how TorZ/MtsZ mediates this effect we purified and characterized the enzyme, and were able to show that it is an S- and N-oxide reductase with a stereospecificity for S-sulfoxides. The enzyme converts two physiologically relevant sulfoxides, biotin sulfoxide and methionine sulfoxide (MetSO), with the kinetic parameters suggesting that MetSO is the natural substrate of this enzyme. TorZ/MtsZ was unable to repair sulfoxides in oxidized Calmodulin, suggesting that a role in cell metabolism/energy generation and not protein repair is the key function of this enzyme. Phylogenetic analyses showed thatH. influenzaeTorZ/MtsZ is only distantly related to theEscherichia coliTorZ TMAO reductase, but instead is a representative of a new, previously uncharacterized clade of molybdenum enzyme that is widely distributed within the Pasteurellaceae family of pathogenic bacteria. It is likely that MtsZ/TorZ has a similar role in supporting host/pathogen interactions in other members of the Pasteurellaceae, which includes both human and animal pathogens.
authors.affiliation: Centre for Metals in Biology/Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia QLD, Australia.
authors.forename: Rabeb
authors.initials: R
authors.lastname: Dhouib
authors.affiliation: Centre for Metals in Biology/Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia QLD, Australia.
authors.forename: Dk Seti Maimonah Pg
authors.initials: DS
authors.lastname: Othman
authors.affiliation: Centre for Metals in Biology/Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia QLD, Australia.
authors.forename: Victor
authors.initials: V
authors.lastname: Lin
authors.affiliation: Centre for Metals in Biology/Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia QLD, Australia.
authors.forename: Xuanjie J
authors.initials: XJ
authors.lastname: Lai
authors.affiliation: Centre for Metals in Biology/Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia QLD, Australia.
authors.forename: Hewa G S
authors.initials: HG
authors.lastname: Wijesinghe
authors.affiliation: Centre for Asthma and Respiratory Diseases, Hunter Medical Research Institute, The University of Newcastle, New Lambton NSW, Australia.
authors.forename: Ama-Tawiah
authors.initials: AT
authors.lastname: Essilfie
authors.affiliation: Centre for Metals in Biology/Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. LuciaQLD, Australia; Department of Chemistry and Biochemistry, The University of Arizona, TucsonAZ, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Davis
authors.affiliation: Centre for Metals in Biology/Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia QLD, Australia.
authors.forename: Marufa
authors.initials: M
authors.lastname: Nasreen
authors.affiliation: Centre for Metals in Biology/Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia QLD, Australia.
authors.forename: Paul V
authors.initials: PV
authors.lastname: Bernhardt
authors.affiliation: Centre for Asthma and Respiratory Diseases, Hunter Medical Research Institute, The University of Newcastle, New Lambton NSW, Australia.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Hansbro
authors.affiliation: Centre for Metals in Biology/Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia QLD, Australia.
authors.forename: Alastair G
authors.initials: AG
authors.lastname: McEwan
authors.affiliation: Centre for Metals in Biology/Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia QLD, Australia.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Kappler
keywords: DMSO reductase enzyme family; Haemophilus influenzae; host–pathogen interaction; methionine sulfoxide reductase; molybdenum enzymes