title: Three-dimensional structure and biophysical characterization of Staphylococcus aureus cell surface antigen-manganese transporter MntC.
abstract: MntC is a metal-binding protein component of the Mn²⁺-specific mntABC transporter from the pathogen Staphylococcus aureus. The protein is expressed during the early stages of infection and was proven to be effective at reducing both S. aureus and Staphylococcus epidermidis infections in a murine animal model when used as a vaccine antigen. MntC is currently being tested in human clinical trials as a component of a multiantigen vaccine for the prevention of S. aureus infections. To better understand the biological function of MntC, we are providing structural and biophysical characterization of the protein in this work. The three-dimensional structure of the protein was solved by X-ray crystallography at 2.2Å resolution and suggests two potential metal binding modes, which may lead to reversible as well as irreversible metal binding. Precise Mn²⁺-binding affinity of the protein was determined from the isothermal titration calorimetry experiments using a competition approach. Differential scanning calorimetry experiments confirmed that divalent metals can indeed bind to MntC reversibly as well as irreversibly. Finally, Mn²⁺-induced structural and dynamics changes have been characterized using spectroscopic methods and deuterium-hydrogen exchange mass spectroscopy. Results of the experiments show that these changes are minimal and are largely restricted to the structural elements involved in metal coordination. Therefore, it is unlikely that antibody binding to this antigen will be affected by the occupancy of the metal-binding site by Mn²⁺.
authors.affiliation: Pfizer Vaccine Research, 401 North Middletown Road, Pearl River, NY 10965, USA. Alexey.Gribenko@pfizer.com
authors.forename: Alexey
authors.initials: A
authors.lastname: Gribenko
authors.forename: Lidia
authors.initials: L
authors.lastname: Mosyak
authors.forename: Sharmistha
authors.initials: S
authors.lastname: Ghosh
authors.forename: Kevin
authors.initials: K
authors.lastname: Parris
authors.forename: Kristine
authors.initials: K
authors.lastname: Svenson
authors.forename: Justin
authors.initials: J
authors.lastname: Moran
authors.forename: Ling
authors.initials: L
authors.lastname: Chu
authors.forename: Sheng
authors.initials: S
authors.lastname: Li
authors.forename: Tong
authors.initials: T
authors.lastname: Liu
authors.forename: Virgil L
authors.initials: VL
authors.lastname: Woods
authors.forename: Kathrin U
authors.initials: KU
authors.lastname: Jansen
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Green
authors.forename: Annaliesa S
authors.initials: AS
authors.lastname: Anderson
authors.forename: Yury V
authors.initials: YV
authors.lastname: Matsuka
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D000954:Antigens, Surface / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D055592:Biophysical Phenomena; D002151:Calorimetry / Q000379:methods; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D041961:Deuterium Exchange Measurement; D057927:Hydrophobic and Hydrophilic Interactions; D008345:Manganese / Q000378:metabolism*; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D033902:Periplasmic Binding Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D013211:Staphylococcus aureus / Q000235:genetics / Q000378:metabolism
chemical_list: D018528:ATP-Binding Cassette Transporters; D000954:Antigens, Surface; D033902:Periplasmic Binding Proteins; D008345:Manganese
keywords: ABC; ABC transporter; ATP-binding cassette; DSC; DXMS; EDTA; HIC; ITC; MntC; PBS; calorimetry; deuterium–hydrogen exchange mass spectroscopy; differential scanning calorimetry; ethylenediaminetetraacetic acid; hydrophobic interaction chromatography; isothermal titration calorimetry; manganese binding; phosphate-buffered saline; vaccine candidate