4zmc
From Proteopedia
Crystal structure of the PmFTN variant E130A soaked in iron (5 min)
Structural highlights
FunctionB6DMH6_PSEMU Stores iron in a soluble, non-toxic, readily available form. Important for iron homeostasis. Iron is taken up in the ferrous form and deposited as ferric hydroxides after oxidation.[RuleBase:RU361145] Publication Abstract from PubMedFerritin from the marine pennate diatom Pseudo-nitzschia multiseries (PmFTN) plays a key role in sustaining growth in iron-limited ocean environments. The di-iron catalytic ferroxidase center of PmFTN (sites A and B) has a nearby third iron site (site C) in an arrangement typically observed in prokaryotic ferritins. Here we demonstrate that Glu44, a site C ligand, and Glu130, a residue that bridges iron bound at sites B and C, limit the rate of post-oxidation reorganization of iron coordination and the rate at which Fe3+ exits the ferroxidase center for storage within the mineral core. The latter, in particular, severely limits the overall rate of iron mineralization. Thus, the diatom ferritin is optimized for initial Fe2+ oxidation but not for mineralization, pointing to a role for this protein in buffering iron availability and facilitating iron-sparing rather than only long-term iron storage. A Diatom Ferritin Optimized for Iron Oxidation but not Iron Storage.,Pfaffen S, Bradley JM, Abdulqadir R, Firme MR, Moore GR, Le Brun NE, Murphy ME J Biol Chem. 2015 Sep 22. pii: jbc.M115.669713. PMID:26396187[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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