title: NMR study of the exchange coupling in the trinuclear cluster of the multicopper oxidase Fet3p.
abstract: Fet3p from Saccharomyces cerevisiae is a multicopper oxidase (MCO) which oxidizes Fe(2+) to Fe(3+). The electronic structure of the different copper centers in this family of enzymes has been extensively studied and discussed for years with a particular focus on the exchange coupling regime in the trinuclear cluster (TNC). Using NMR spectroscopy we have quantified the exchange coupling constant in the type 3 center in a fully metalated oxidase; this value in Fet3p is significantly higher than that reported for proteins containing isolated type 3 centers as tyrosinase. We also provide evidence of exchange coupling between the type 2 and the type 3 Cu(2+) ions, which supports the crystallographic evidence of dioxygen binding to the TNC. This work provides the foundation for the application of NMR to these complex systems.
authors.affiliation: IBR (Instituto de Biología Molecular y Celular de Rosario), CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, (S2002LRK), Rosario, Argentina.
authors.forename: María-Eugenia
authors.initials: ME
authors.lastname: Zaballa
authors.forename: Lynn
authors.initials: L
authors.lastname: Ziegler
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Kosman
authors.forename: Alejandro J
authors.initials: AJ
authors.lastname: Vila
mesh_terms: D002570:Ceruloplasmin / Q000737:chemistry* / Q000378:metabolism; D003300:Copper; D004578:Electron Spin Resonance Spectroscopy; D008024:Ligands; D008280:Magnetics; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D011487:Protein Conformation; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000378:metabolism; D013696:Temperature
chemical_list: D008024:Ligands; D029701:Saccharomyces cerevisiae Proteins; D003300:Copper; D002570:Ceruloplasmin; C085513:FET3 protein, S cerevisiae