title: Impact of copper ligand mutations on a cupredoxin with a green copper center.
abstract: Mononuclear cupredoxins contain a type 1 copper center with a trigonal or tetragonal geometry usually maintained by four ligands, a cystein, two histidines and a methionine. The recent discovery of new members of this family with unusual properties demonstrates, however, the versatility of this class of proteins. Changes in their ligand set lead to drastic variation in their metal site geometry and in the resulting spectroscopic and redox features. In our work, we report the identification of the copper ligands in the recently discovered cupredoxin AcoP. We show that even though AcoP possesses a classical copper ligand set, it has a highly perturbed copper center. In depth studies of mutant's properties suggest a high degree of constraint existing in the copper center of the wild type protein and even the addition of exogenous ligands does not lead to the reconstitution of the initial copper center. Not only the chemical nature of the axial ligand but also constraints brought by its covalent binding to the protein backbone might be critical to maintain a green copper site with high redox potential. This work illustrates the importance of experimentally dissecting the molecular diversity of cupredoxins to determine the molecular determinants responsible for their copper center geometry and redox potential.
authors.affiliation: Aix-Marseille Univ, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, 13009 Marseille Cedex 20, France.
authors.forename: Magali
authors.initials: M
authors.lastname: Roger
authors.affiliation: Aix-Marseille Univ, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, 13009 Marseille Cedex 20, France.
authors.forename: Giuliano
authors.initials: G
authors.lastname: Sciara
authors.affiliation: Aix-Marseille Univ, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, 13009 Marseille Cedex 20, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Biaso
authors.affiliation: Aix-Marseille Univ, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, 13009 Marseille Cedex 20, France.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Lojou
authors.affiliation: Aix-Marseille Univ, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, 13009 Marseille Cedex 20, France.
authors.forename: Xie
authors.initials: X
authors.lastname: Wang
authors.affiliation: Aix Marseille Univ, CNRS, Unité de Fermentation, FR 3479, 31 chemin J. Aiguier, 13009 Marseille Cedex 20, France.
authors.forename: Marielle
authors.initials: M
authors.lastname: Bauzan
authors.affiliation: Aix-Marseille Univ, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, 13009 Marseille Cedex 20, France.
authors.forename: Marie-Thérèse
authors.initials: MT
authors.lastname: Giudici-Orticoni
authors.affiliation: Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Rosario, Argentina; Área Biofísica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario, Argentina.
authors.forename: Alejandro J
authors.initials: AJ
authors.lastname: Vila
authors.affiliation: Aix-Marseille Univ, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, 13009 Marseille Cedex 20, France. Electronic address: milbert@imm.cnrs.fr.
authors.forename: Marianne
authors.initials: M
authors.lastname: Ilbert
mesh_terms: D042763:Acidithiobacillus / Q000235:genetics / Q000378:metabolism*; D001400:Azurin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D002942:Circular Dichroism; D003300:Copper / Q000737:chemistry / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D005838:Genotype; D006863:Hydrogen-Ion Concentration; D008024:Ligands; D009154:Mutation; D010084:Oxidation-Reduction; D010641:Phenotype; D011485:Protein Binding; D011487:Protein Conformation; D013056:Spectrophotometry, Ultraviolet; D013329:Structure-Activity Relationship; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D008024:Ligands; C050107:cupredoxin; D001400:Azurin; D003300:Copper
keywords: Acidithiobacillus ferrooxidans; Copper; Cupredoxin; Green copper site; Metal center; Metalloprotein