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Mechanism of Ferrous Iron Binding and Oxidation by Ferritin from a Pennate Diatom

A novel ferritin was recently found in Pseudo-nitzschia multiseries (PmFTN), a marine pennate diatom that plays a major role in global primary production and carbon sequestration into the deep ocean. Crystals of recombinant PmFTN were soaked in iron and zinc solutions, and the structures were solved...

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Autores principales: Pfaffen, Stephanie, Abdulqadir, Raz, Le Brun, Nick E., Murphy, Michael E. P.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Society for Biochemistry and Molecular Biology 2013
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3663513/
https://www.ncbi.nlm.nih.gov/pubmed/23548912
http://dx.doi.org/10.1074/jbc.M113.454496
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author Pfaffen, Stephanie
Abdulqadir, Raz
Le Brun, Nick E.
Murphy, Michael E. P.
author_facet Pfaffen, Stephanie
Abdulqadir, Raz
Le Brun, Nick E.
Murphy, Michael E. P.
author_sort Pfaffen, Stephanie
collection PubMed
description A novel ferritin was recently found in Pseudo-nitzschia multiseries (PmFTN), a marine pennate diatom that plays a major role in global primary production and carbon sequestration into the deep ocean. Crystals of recombinant PmFTN were soaked in iron and zinc solutions, and the structures were solved to 1.65–2.2-Å resolution. Three distinct iron binding sites were identified as determined from anomalous dispersion data from aerobically grown ferrous soaked crystals. Sites A and B comprise the conserved ferroxidase active site, and site C forms a pathway leading toward the central cavity where iron storage occurs. In contrast, crystal structures derived from anaerobically grown and ferrous soaked crystals revealed only one ferrous iron in the active site occupying site A. In the presence of dioxygen, zinc is observed bound to all three sites. Iron oxidation experiments using stopped-flow absorbance spectroscopy revealed an extremely rapid phase corresponding to Fe(II) oxidation at the ferroxidase site, which is saturated after adding 48 ferrous iron to apo-PmFTN (two ferrous iron per subunit), and a much slower phase due to iron core formation. These results suggest an ordered stepwise binding of ferrous iron and dioxygen to the ferroxidase site in preparation for catalysis and a partial mobilization of iron from the site following oxidation.
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spelling pubmed-36635132013-05-28 Mechanism of Ferrous Iron Binding and Oxidation by Ferritin from a Pennate Diatom Pfaffen, Stephanie Abdulqadir, Raz Le Brun, Nick E. Murphy, Michael E. P. J Biol Chem Enzymology A novel ferritin was recently found in Pseudo-nitzschia multiseries (PmFTN), a marine pennate diatom that plays a major role in global primary production and carbon sequestration into the deep ocean. Crystals of recombinant PmFTN were soaked in iron and zinc solutions, and the structures were solved to 1.65–2.2-Å resolution. Three distinct iron binding sites were identified as determined from anomalous dispersion data from aerobically grown ferrous soaked crystals. Sites A and B comprise the conserved ferroxidase active site, and site C forms a pathway leading toward the central cavity where iron storage occurs. In contrast, crystal structures derived from anaerobically grown and ferrous soaked crystals revealed only one ferrous iron in the active site occupying site A. In the presence of dioxygen, zinc is observed bound to all three sites. Iron oxidation experiments using stopped-flow absorbance spectroscopy revealed an extremely rapid phase corresponding to Fe(II) oxidation at the ferroxidase site, which is saturated after adding 48 ferrous iron to apo-PmFTN (two ferrous iron per subunit), and a much slower phase due to iron core formation. These results suggest an ordered stepwise binding of ferrous iron and dioxygen to the ferroxidase site in preparation for catalysis and a partial mobilization of iron from the site following oxidation. American Society for Biochemistry and Molecular Biology 2013-05-24 2013-04-02 /pmc/articles/PMC3663513/ /pubmed/23548912 http://dx.doi.org/10.1074/jbc.M113.454496 Text en © 2013 by The American Society for Biochemistry and Molecular Biology, Inc. Author's Choice—Final version full access. Creative Commons Attribution Unported License (http://creativecommons.org/licenses/by/3.0/) applies to Author Choice Articles
spellingShingle Enzymology
Pfaffen, Stephanie
Abdulqadir, Raz
Le Brun, Nick E.
Murphy, Michael E. P.
Mechanism of Ferrous Iron Binding and Oxidation by Ferritin from a Pennate Diatom
title Mechanism of Ferrous Iron Binding and Oxidation by Ferritin from a Pennate Diatom
title_full Mechanism of Ferrous Iron Binding and Oxidation by Ferritin from a Pennate Diatom
title_fullStr Mechanism of Ferrous Iron Binding and Oxidation by Ferritin from a Pennate Diatom
title_full_unstemmed Mechanism of Ferrous Iron Binding and Oxidation by Ferritin from a Pennate Diatom
title_short Mechanism of Ferrous Iron Binding and Oxidation by Ferritin from a Pennate Diatom
title_sort mechanism of ferrous iron binding and oxidation by ferritin from a pennate diatom
topic Enzymology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3663513/
https://www.ncbi.nlm.nih.gov/pubmed/23548912
http://dx.doi.org/10.1074/jbc.M113.454496
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