title: Probing in vivo Mn2+ speciation and oxidative stress resistance in yeast cells with electron-nuclear double resonance spectroscopy.
abstract: Manganese is an essential transition metal that, among other functions, can act independently of proteins to either defend against or promote oxidative stress and disease. The majority of cellular manganese exists as low molecular-weight Mn(2+) complexes, and the balance between opposing "essential" and "toxic" roles is thought to be governed by the nature of the ligands coordinating Mn(2+). Until now, it has been impossible to determine manganese speciation within intact, viable cells, but we here report that this speciation can be probed through measurements of (1)H and (31)P electron-nuclear double resonance (ENDOR) signal intensities for intracellular Mn(2+). Application of this approach to yeast (Saccharomyces cerevisiae) cells, and two pairs of yeast mutants genetically engineered to enhance or suppress the accumulation of manganese or phosphates, supports an in vivo role for the orthophosphate complex of Mn(2+) in resistance to oxidative stress, thereby corroborating in vitro studies that demonstrated superoxide dismutase activity for this species.
authors: Department of Chemistry, Northwestern University, Evanston, IL 60208, USA.
authors: Rebecca L
authors: RL
authors: McNaughton
authors: Amit R
authors: AR
authors: Reddi
authors: Matthew H S
authors: MH
authors: Clement
authors: Ajay
authors: A
authors: Sharma
authors: Kevin
authors: K
authors: Barnese
authors: Leah
authors: L
authors: Rosenfeld
authors: Edith Butler
authors: EB
authors: Gralla
authors: Joan Selverstone
authors: JS
authors: Valentine
authors: Valeria C
authors: VC
authors: Culotta
authors: Brian M
authors: BM
authors: Hoffman
mesh_terms: D000465:Algorithms; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods*; D006706:Homeostasis; D007700:Kinetics; D008345:Manganese / Q000737:chemistry* / Q000378:metabolism; D008956:Models, Chemical; D009154:Mutation; D018384:Oxidative Stress; D010100:Oxygen / Q000378:metabolism; D010710:Phosphates / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D013054:Spectrophotometry, Atomic; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D010710:Phosphates; D008345:Manganese; D013482:Superoxide Dismutase; D010100:Oxygen