title: Spectral and thermodynamic properties of methanobactin from γ-proteobacterial methane oxidizing bacteria: a case for copper competition on a molecular level.
abstract: Methanobactin (mb) is a low molecular mass copper-binding molecule analogous to iron-binding siderophores. The molecule is produced by many methanotrophic or methane oxidizing bacteria (MOB), but has only been characterized to date in one MOB, Methylosinus trichosporium OB3b. To explore the potential molecular diversity in this novel class of metal binding compound, the spectral (UV-visible, fluorescent, and electron paramagnetic resonance) and thermodynamic properties of mb from two γ-proteobacterial MOB, Methylococcus capsulatus Bath and Methylomicrobium album BG8, were determined and compared to the mb from the α-proteobacterial MOB, M. trichosporium OB3b. The mb from both γ-proteobacterial MOB differed from the mb from M. trichosporium OB3b in molecular mass and spectral properties. Compared to mb from M. trichosporium OB3b, the extracellular concentrations were low, as were copper-binding constants of mb from both γ-proteobacterial MOB. In addition, the mb from M. trichosporium OB3b removed Cu(I) from the mb of both γ-proteobacterial MOB. Taken together the results suggest mb may be a factor in regulating methanotrophic community structure in copper-limited environments.
authors.affiliation: Department of Biochemistry, Biophysics and Molecular Biology Iowa State University, Ames, IA 50011-3211, United States.
authors.forename: Dong W
authors.initials: DW
authors.lastname: Choi
authors.forename: Nathan L
authors.initials: NL
authors.lastname: Bandow
authors.forename: Marcus T
authors.initials: MT
authors.lastname: McEllistrem
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Semrau
authors.forename: William E
authors.initials: WE
authors.lastname: Antholine
authors.forename: Scott C
authors.initials: SC
authors.lastname: Hartsel
authors.forename: Warren
authors.initials: W
authors.lastname: Gallagher
authors.forename: Corbin J
authors.initials: CJ
authors.lastname: Zea
authors.forename: Nicole L
authors.initials: NL
authors.lastname: Pohl
authors.forename: James A
authors.initials: JA
authors.lastname: Zahn
authors.forename: Alan A
authors.initials: AA
authors.lastname: DiSpirito
mesh_terms: D003300:Copper / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D020563:Gammaproteobacteria / Q000737:chemistry; D007093:Imidazoles / Q000737:chemistry* / Q000378:metabolism*; D008772:Methylococcaceae / Q000737:chemistry*; D020619:Methylococcus capsulatus / Q000737:chemistry; D020602:Methylosinus trichosporium / Q000737:chemistry; D008954:Models, Biological; D009842:Oligopeptides / Q000737:chemistry* / Q000378:metabolism*; D013816:Thermodynamics
chemical_list: D007093:Imidazoles; D009842:Oligopeptides; C491147:methanobactin; D003300:Copper