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Three Aromatic Residues are Required for Electron Transfer during Iron Mineralization in Bacterioferritin.
Bradley, Justin M; Svistunenko, Dimitri A; Lawson, Tamara L; Hemmings, Andrew M; Moore, Geoffrey R; Le Brun, Nick E.
Afiliação
  • Bradley JM; Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ (UK).
  • Svistunenko DA; School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester CO4 3SQ (UK).
  • Lawson TL; Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ (UK).
  • Hemmings AM; Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ (UK).
  • Moore GR; School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ (UK).
  • Le Brun NE; Centre for Molecular and Structural Biochemistry, School of Chemistry, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ (UK).
Angew Chem Int Ed Engl ; 54(49): 14763-7, 2015 Dec 01.
Article em En | MEDLINE | ID: mdl-26474305
Ferritins are iron storage proteins that overcome the problems of toxicity and poor bioavailability of iron by catalyzing iron oxidation and mineralization through the activity of a diiron ferroxidase site. Unlike in other ferritins, the oxidized di-Fe(3+) site of Escherichia coli bacterioferritin (EcBFR) is stable and therefore does not function as a conduit for the transfer of Fe(3+) into the storage cavity, but instead acts as a true catalytic cofactor that cycles its oxidation state while driving Fe(2+) oxidation in the cavity. Herein, we demonstrate that EcBFR mineralization depends on three aromatic residues near the diiron site, Tyr25, Tyr58, and Trp133, and that a transient radical is formed on Tyr25. The data indicate that the aromatic residues, together with a previously identified inner surface iron site, promote mineralization by ensuring the simultaneous delivery of two electrons, derived from Fe(2+) oxidation in the BFR cavity, to the di-ferric catalytic site for safe reduction of O2.
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Texto completo: 1 Base de dados: MEDLINE Assunto principal: Proteínas de Bactérias / Grupo dos Citocromos b / Ferritinas / Ferro Idioma: En Ano de publicação: 2015 Tipo de documento: Article

Texto completo: 1 Base de dados: MEDLINE Assunto principal: Proteínas de Bactérias / Grupo dos Citocromos b / Ferritinas / Ferro Idioma: En Ano de publicação: 2015 Tipo de documento: Article