title: The copper chelator methanobactin from Methylosinus trichosporium OB3b binds copper(I).
abstract: The oxidation state of copper bound to methanobactin, a small siderophore-like molecule from the methanotroph Methylosinus trichosporium OB3b, was investigated. Purified methanobactin loaded with Cu(II) exhibits a weak EPR signal probably due to adventitious Cu(II). The EPR signal intensity increases significantly upon addition of the strong oxidant nitric acid. Features of the X-ray absorption near edge spectrum, including a 1s --> 4p transition at 8985 eV, further indicate the presence of Cu(I). EXAFS data were best fit using a multiple scattering model generated from previously reported crystallographic parameters. These results establish definitively that M. trichosporium OB3b methanobactin binds Cu(I) and suggest that methanobactin itself reduces Cu(II) to Cu(I).
authors.affiliation: Department of Biochemistry, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Amanda S
authors.initials: AS
authors.lastname: Hakemian
authors.forename: Christine E
authors.initials: CE
authors.lastname: Tinberg
authors.forename: Kalyan C
authors.initials: KC
authors.lastname: Kondapalli
authors.forename: Joshua
authors.initials: J
authors.lastname: Telser
authors.forename: Brian M
authors.initials: BM
authors.lastname: Hoffman
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Stemmler
authors.forename: Amy C
authors.initials: AC
authors.lastname: Rosenzweig
mesh_terms: D015502:Absorptiometry, Photon; D003300:Copper / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D007093:Imidazoles / Q000737:chemistry / Q000378:metabolism*; D020602:Methylosinus trichosporium / Q000737:chemistry*; D015394:Molecular Structure; D009842:Oligopeptides / Q000737:chemistry / Q000378:metabolism*; D010084:Oxidation-Reduction; D011485:Protein Binding
chemical_list: D007093:Imidazoles; D009842:Oligopeptides; C491147:methanobactin; D003300:Copper