title: X-ray absorption spectroscopy of cuprous-thiolate clusters in Saccharomyces cerevisiae metallothionein.
abstract: Copper (Cu) metallothioneins are cuprous-thiolate proteins that contain multimetallic clusters, and are thought to have dual functions of Cu storage and Cu detoxification. We have used a combination of X-ray absorption spectroscopy (XAS) and density-functional theory (DFT) to investigate the nature of Cu binding to Saccharomyces cerevisiae metallothionein. We found that the XAS of metallothionein prepared, containing a full complement of Cu, was quantitatively consistent with the crystal structure, and that reconstitution of the apo-metallothionein with stoichiometric Cu results in the formation of a tetracopper cluster, indicating cooperative binding of the Cu ions by the metallothionein.
authors.affiliation: Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, S7N 5E2, Canada (phone: +1-306-966 5722; fax: +1-306-966 8593).
authors.forename: Limei
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, S7N 5E2, Canada (phone: +1-306-966 5722; fax: +1-306-966 8593).
authors.forename: Ingrid J
authors.initials: IJ
authors.lastname: Pickering
authors.affiliation: Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, S7N 5E2, Canada (phone: +1-306-966 5722; fax: +1-306-966 8593).
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Winge
authors.affiliation: Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, S7N 5E2, Canada (phone: +1-306-966 5722; fax: +1-306-966 8593).
authors.forename: Graham N
authors.initials: GN
authors.lastname: George
mesh_terms: D015502:Absorptiometry, Photon; D001665:Binding Sites; D003300:Copper / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D008668:Metallothionein / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D011485:Protein Binding; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry* / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D029701:Saccharomyces cerevisiae Proteins; D013438:Sulfhydryl Compounds; C042514:cuprous ion; D003300:Copper; D008668:Metallothionein