title: Metal binding specificity of the MntABC permease of Neisseria gonorrhoeae and its influence on bacterial growth and interaction with cervical epithelial cells.
abstract: mntABC from Neisseria gonorrhoeae encodes an ABC permease which includes a periplasmic divalent cation binding receptor protein of the cluster IX family, encoded by mntC. Analysis of an mntC mutant showed that growth of N. gonorrhoeae could be stimulated by addition of either manganese(II) or zinc(II) ions, suggesting that the MntABC system could transport both ions. In contrast, growth of the mntAB mutant in liquid culture was possible only when the medium was supplemented with an antioxidant such as mannitol, consistent with the view that ion transport via MntABC is essential for protection of N. gonorrhoeae against oxidative stress. Using recombinant MntC, we determined that MntC binds Zn(2+) and Mn(2+) with almost equal affinity (dissociation constant of approximately 0.1 microM). Competition assays with the metallochromic zinc indicator 4-(2-pyridylazo)resorcinol showed that MntC binds Mn(2+) and Zn(2+) at the same binding site. Analysis of the N. gonorrhoeae genome showed that MntC is the only Mn/Zn metal binding receptor protein cluster IX in this bacterium, in contrast to the situation in many other bacteria which have systems with dedicated Mn and Zn binding proteins as part of distinctive ABC cassette permeases. Both the mntC and mntAB mutants had reduced intracellular survival in a human cervical epithelial cell model and showed reduced ability to form a biofilm. These data suggest that the MntABC transporter is of importance for survival of Neisseria gonorrhoeae in the human host.
authors.affiliation: School of Molecular and Microbial Sciences, The University of Queensland, St. Lucia 4072, Australia.
authors.forename: Karen H L
authors.initials: KH
authors.lastname: Lim
authors.forename: Christopher E
authors.initials: CE
authors.lastname: Jones
authors.forename: Rachel N
authors.initials: RN
authors.lastname: vanden Hoven
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Edwards
authors.forename: Megan L
authors.initials: ML
authors.lastname: Falsetta
authors.forename: Michael A
authors.initials: MA
authors.lastname: Apicella
authors.forename: Michael P
authors.initials: MP
authors.lastname: Jennings
authors.forename: Alastair G
authors.initials: AG
authors.lastname: McEwan
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D018441:Biofilms / Q000254:growth & development; D002413:Cations, Divalent / Q000378:metabolism*; D002460:Cell Line; D002584:Cervix Uteri / Q000166:cytology / Q000382:microbiology*; D004847:Epithelial Cells / Q000382:microbiology; D005260:Female; D006801:Humans; D007700:Kinetics; D026901:Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D008670:Metals / Q000378:metabolism*; D009344:Neisseria gonorrhoeae / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development / Q000472:pathogenicity*; D033902:Periplasmic Binding Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D002413:Cations, Divalent; D026901:Membrane Transport Proteins; D008670:Metals; C432956:MntC protein, Neisseria gonorrhoeae; D033902:Periplasmic Binding Proteins