title: XAS examination of glutathione-cobalt complexes in solution.
abstract: In the present work, we have investigated the coordination modes of cobalt with glutathione (γ-l-glutamyl-l-cysteinyl-glycine, GSH). A systematic study of cobalt-GSH complexes at basic and neutral pH has been undertaken with a multi-spectroscopic approach combined with quantum chemistry calculations. XAS (x-ray absorption spectroscopy) has been performed at the cobalt K edge in order to shed light into the cation coordination sphere and formal oxidation states. XANES (x-ray absorption near edge structure) enabled to show that in basic and neutral media, cobalt oxidation state is equal to +III and +II respectively. EXAFS (extended x-ray absorption fine structure) provided indications on the donor atoms involved in the coordination with cobalt as well as the bond lengths. DFT (density functional theory)-based calculations and NMR experiments have been performed to assess the most stable structure of the cobalt-GSH complex in basic conditions.
authors.affiliation: CEADEN, DPC, SEARS, Laboratoire de développement Analytique Nucléaire, Isotopique et Elémentaire, F-91191 Gif-sur-Yvette, France. Electronic address: carole.bresson@cea.fr.
authors.forename: Carole
authors.initials: C
authors.lastname: Bresson
authors.affiliation: CNRS, LAMBE UMR 8587, Université d'Evry-Val-d'Essonne, 91025 Evry Cedex, France.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Spezia
authors.affiliation: Synchrotron SOLEILMARS Beamline, L'Orme des Merisiers, Saint Aubin BP 48, F-91192 Gif sur Yvette Cedex, France.
authors.forename: Pier Lorenzo
authors.initials: PL
authors.lastname: Solari
authors.affiliation: CEADEN, DPC, SEARS, Laboratoire de développement Analytique Nucléaire, Isotopique et Elémentaire, F-91191 Gif-sur-Yvette, France; Département de Chimie et Biochimie, Université de Moncton, Moncton, NB, E1A 3E9, Canada.
authors.forename: Christopher K
authors.initials: CK
authors.lastname: Jankowski
authors.affiliation: Université de Nice Sophia Antipolis, Institut de Chimie de Nice UMR7272, 06108 Nice, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Den Auwer
mesh_terms: D003035:Cobalt / Q000737:chemistry*; D056831:Coordination Complexes / Q000737:chemistry*; D005978:Glutathione / Q000737:chemistry*; D056928:X-Ray Absorption Spectroscopy
chemical_list: D056831:Coordination Complexes; D003035:Cobalt; D005978:Glutathione
keywords: Cobalt; DFT; Glutathione; NMR; XAS