title: Dimerization interface and dynamic properties of yeast IF1 revealed by Site-Directed Spin Labeling EPR spectroscopy.
abstract: The mitochondrial ATPase inhibitor, IF1, regulates the activity of the mitochondrial ATP synthase. The oligomeric state of IF1 related to pH is crucial for its inhibitory activity. Although extensive structural studies have been performed to characterize the oligomeric states of bovine IF1, only little is known concerning those of yeast IF1. While bovine IF1 can be found as an inhibitory dimer at low pH and a non-inhibitory tetramer at high pH, a monomer/dimer equilibrium has been described for yeast IF1, high pH values favoring the monomeric state. Combining different strategies involving the grafting of nitroxide spin labels combined with Electron Paramagnetic Resonance (EPR) spectroscopy, the present study brings the first structural characterization, at the residue level, of yeast IF1 in its dimeric form. The results show that the dimerization interface involves the central region of the peptide revealing that the dimer corresponds to a non-inhibitory state. Moreover, we demonstrate that the C-terminal region of the peptide is highly dynamic and that this segment is probably folded back onto the central region. Finally, the pH-dependence of the inter-label distance distribution has been observed indicating a conformational change between two structural states in the dimer.
authors.affiliation: Aix-Marseille Université, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, F-13402 Marseille, France.
authors.forename: Nolwenn
authors.initials: N
authors.lastname: Le Breton
authors.affiliation: Lifesearch, 72 rue du Fauboug St Honoré, F-75008 Paris, France; CEA, Institut de Biologie et de Technologies de Saclay IBITECS, SB2SM, F-91191 Gif sur Yvette, France; CEA, CNRS, Université Paris Sud, Institut de Biologie Intégrative de la Cellule I2BC, UMR 9198, F-91191 Gif sur Yvette, France.
authors.forename: Tiona
authors.initials: T
authors.lastname: Adrianaivomananjaona
authors.affiliation: Aix-Marseille Université, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, F-13402 Marseille, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Gerbaud
authors.affiliation: Aix-Marseille Université, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, F-13402 Marseille, France.
authors.forename: Emilien
authors.initials: E
authors.lastname: Etienne
authors.affiliation: CEA, Institut de Biologie et de Technologies de Saclay IBITECS, SB2SM, F-91191 Gif sur Yvette, France; Department of Biomedical Sciences and Technologies, University of Udine, Piazzale Kolbe 4, I-33100 Udine, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Bisetto
authors.affiliation: University Bordeaux-CNRS, IBGC, UMR 5095, 1 rue Camille Saint-Saëns, F-33000 Bordeaux, France.
authors.forename: Alain
authors.initials: A
authors.lastname: Dautant
authors.affiliation: Aix-Marseille Université, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, F-13402 Marseille, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Guigliarelli
authors.affiliation: CEA, Institut de Biologie et de Technologies de Saclay IBITECS, SB2SM, F-91191 Gif sur Yvette, France; CEA, CNRS, Université Paris Sud, Institut de Biologie Intégrative de la Cellule I2BC, UMR 9198, F-91191 Gif sur Yvette, France. Electronic address: francis.haraux@cea.fr.
authors.forename: Francis
authors.initials: F
authors.lastname: Haraux
authors.affiliation: Aix-Marseille Université, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, F-13402 Marseille, France.
authors.forename: Marlène
authors.initials: M
authors.lastname: Martinho
authors.affiliation: Aix-Marseille Université, CNRS, BIP UMR 7281, 31 chemin J. Aiguier, F-13402 Marseille, France. Electronic address: belle@imm.cnrs.fr.
authors.forename: Valérie
authors.initials: V
authors.lastname: Belle
mesh_terms: D000595:Amino Acid Sequence; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008969:Molecular Sequence Data; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D011506:Proteins / Q000737:chemistry*; D012441:Saccharomyces cerevisiae / Q000737:chemistry*; D000097795:ATPase Inhibitory Protein
chemical_list: D011506:Proteins; D000097795:ATPase Inhibitory Protein
keywords: ATP synthase; Dimerization interface; IF1 inhibitory peptide; Protein dynamics; Yeast