title: In situ determination of manganese(II) speciation in Deinococcus radiodurans by high magnetic field EPR: detection of high levels of Mn(II) bound to proteins.
abstract: High magnetic field high frequency electron paramagnetic resonance techniques were used to measure in situ Mn(II) speciation in Deinococcus radiodurans, a radiation-resistant bacteria capable of accumulating high concentrations of Mn(II). It was possible to identify and quantify the evolution of Mn(II) species in intact cells at various stages of growth. Aside from water, 95-GHz high field electron nuclear double resonance showed that the Mn(II) ions are bound to histidines and phosphate groups, mostly from fructose-1,6-bisphosphate but also inorganic phosphates and nucleotides. During stationary growth phase, 285-GHz continuous wave EPR measurements showed that histidine is the most common ligand to Mn(II) and that significant amounts of cellular Mn(II) in D. radiodurans are bound to peptides and proteins. As much as 40% of the total Mn(II) was in manganese superoxide dismutase, and it is this protein and not smaller manganese complexes, as has been suggested recently, that is probably the primary defense against superoxide.
authors.affiliation: Service de Bioénergétique, Biologie Structurale et Mécanismes, CNRS/UMR-8221, Institut de Biologie et de Technologies de Saclay, Commissariat à l'Energie Atomique-Saclay, 91191 Gif-sur-Yvette, France. leandro.tabares@cea.fr
authors.forename: Leandro C
authors.initials: LC
authors.lastname: Tabares
authors.forename: Sun
authors.initials: S
authors.lastname: Un
mesh_terms: D004247:DNA / Q000737:chemistry; D034301:Deinococcus / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D006706:Homeostasis; D007477:Ions; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008345:Manganese / Q000737:chemistry*; D009711:Nucleotides / Q000737:chemistry; D018384:Oxidative Stress; D010710:Phosphates / Q000737:chemistry; D011485:Protein Binding; D013482:Superoxide Dismutase; D013481:Superoxides / Q000378:metabolism; D013997:Time Factors
chemical_list: D007477:Ions; D008024:Ligands; D009711:Nucleotides; D010710:Phosphates; D013481:Superoxides; D008345:Manganese; D004247:DNA; D013482:Superoxide Dismutase