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Multicopper manganese oxidase accessory proteins bind Cu and heme.
Butterfield, Cristina N; Tao, Lizhi; Chacón, Kelly N; Spiro, Thomas G; Blackburn, Ninian J; Casey, William H; Britt, R David; Tebo, Bradley M.
Afiliación
  • Butterfield CN; Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health & Science University, Portland, OR 97239, United States.
  • Tao L; Department of Chemistry, University of California, Davis, CA 95616, United States.
  • Chacón KN; Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health & Science University, Portland, OR 97239, United States.
  • Spiro TG; Department of Chemistry, University of Washington, Seattle, WA 98195, United States.
  • Blackburn NJ; Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health & Science University, Portland, OR 97239, United States.
  • Casey WH; Department of Geology, University of California, Davis, CA 95616, United States.
  • Britt RD; Department of Chemistry, University of California, Davis, CA 95616, United States.
  • Tebo BM; Division of Environmental and Biomolecular Systems, Institute of Environmental Health, Oregon Health & Science University, Portland, OR 97239, United States. Electronic address: tebob@ohsu.edu.
Biochim Biophys Acta ; 1854(12): 1853-1859, 2015 Dec.
Article en En | MEDLINE | ID: mdl-26327317
Multicopper oxidases (MCOs) catalyze the oxidation of a diverse group of metal ions and organic substrates by successive single-electron transfers to O2 via four bound Cu ions. MnxG, which catalyzes MnO2 mineralization by oxidizing both Mn(II) and Mn(III), is unique among multicopper oxidases in that it carries out two energetically distinct electron transfers and is tightly bound to accessory proteins. There are two of these, MnxE and MnxF, both approximately 12kDa. Although their sequences are similar to those found in the genomes of several Mn-oxidizing Bacillus species, they are dissimilar to those of proteins with known function. Here, MnxE and MnxF are co-expressed independent of MnxG and are found to oligomerize into a higher order stoichiometry, likely a hexamer. They bind copper and heme, which have been characterized by electron paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS), and UV-visible (UV-vis) spectrophotometry. Cu is found in two distinct type 2 (T2) copper centers, one of which appears to be novel; heme is bound as a low-spin species, implying coordination by two axial ligands. MnxE and MnxF do not oxidize Mn in the absence of MnxG and are the first accessory proteins to be required by an MCO. This may indicate that Cu and heme play roles in electron transfer and/or Cu trafficking.
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Texto completo: 1 Bases de datos: MEDLINE Asunto principal: Óxidos / Compuestos de Manganeso / Cobre / Hemo Idioma: En Revista: Biochim Biophys Acta Año: 2015 Tipo del documento: Article País de afiliación: Estados Unidos

Texto completo: 1 Bases de datos: MEDLINE Asunto principal: Óxidos / Compuestos de Manganeso / Cobre / Hemo Idioma: En Revista: Biochim Biophys Acta Año: 2015 Tipo del documento: Article País de afiliación: Estados Unidos