title: Methanobactin, a copper-acquisition compound from methane-oxidizing bacteria.
abstract: Siderophores are extracellular iron-binding compounds that mediate iron transport into many cells. We present evidence of analogous molecules for copper transport from methane-oxidizing bacteria, represented here by a small fluorescent chromopeptide (C45N12O14H62Cu, 1216 daltons) produced by Methylosinus trichosporium OB3b. The crystal structure of this compound, methanobactin, was resolved to 1.15 angstroms. It is composed of a tetrapeptide, a tripeptide, and several unusual moieties, including two 4-thionyl-5-hydroxy-imidazole chromophores that coordinate the copper, a pyrrolidine that confers a bend in the overall chain, and an amino-terminal isopropylester group. The copper coordination environment includes a dual nitrogen- and sulfur-donating system derived from the thionyl imidazolate moieties. Structural elucidation of this molecule has broad implications in terms of organo-copper chemistry, biological methane oxidation, and global carbon cycling.
authors.affiliation: Department of Civil, Environmental, and Architectural Engineering, University of Kansas, Lawrence, KS 66045, USA.
authors.forename: Hyung J
authors.initials: HJ
authors.lastname: Kim
authors.forename: David W
authors.initials: DW
authors.lastname: Graham
authors.forename: Alan A
authors.initials: AA
authors.lastname: DiSpirito
authors.forename: Michail A
authors.initials: MA
authors.lastname: Alterman
authors.forename: Nadezhda
authors.initials: N
authors.lastname: Galeva
authors.forename: Cynthia K
authors.initials: CK
authors.lastname: Larive
authors.forename: Dan
authors.initials: D
authors.lastname: Asunskis
authors.forename: Peter M A
authors.initials: PM
authors.lastname: Sherwood
mesh_terms: D000596:Amino Acids / Q000032:analysis; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003300:Copper / Q000032:analysis / Q000737:chemistry / Q000378:metabolism*; D003460:Crystallization; D018360:Crystallography, X-Ray; D019281:Dimerization; D007093:Imidazoles / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D008024:Ligands; D008697:Methane / Q000378:metabolism; D020602:Methylosinus trichosporium / Q000737:chemistry / Q000378:metabolism*; D008958:Models, Molecular; D015394:Molecular Structure; D008970:Molecular Weight; D009842:Oligopeptides / Q000737:chemistry* / Q000302:isolation & purification / Q000378:metabolism; D010084:Oxidation-Reduction; D013057:Spectrum Analysis
chemical_list: D000596:Amino Acids; D007093:Imidazoles; D008024:Ligands; D009842:Oligopeptides; C491147:methanobactin; D003300:Copper; D008697:Methane