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A Conserved Tyrosine in Ferritin Is a Molecular Capacitor
Author(s) -
Ebrahimi Kourosh Honarmand,
Hagedoorn PeterLeon,
Hagen Wilfred R.
Publication year - 2013
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201300149
Subject(s) - ferritin , tyrosine , pyrococcus furiosus , chemistry , biochemistry , catalysis , biophysics , biology , archaea , gene
A highly conserved tyrosine residue of unknown function is present in the vicinity of the di‐iron catalytic center of the ubiquitous iron‐storage protein ferritin. The di‐iron center with a gateway Fe II /Fe III ‐binding site nearby provides the vital iron‐storage mechanism of the protein. It is believed that, in eukaryotic ferritin, this center catalyzes simultaneous oxidation of two Fe II ions, whereas in microbial ferritin it catalyzes simultaneous oxidation of three Fe II ions. To understand the role of the conserved tyrosine, we studied the intermediates and products that are formed during catalysis of Fe II oxidation in the di‐iron catalytic centers of the hyperthermophilic archaeal Pyrococcus furiosus ferritin and of eukaryotic human H ferritin. Based on our spectroscopic studies and modeling, we propose a merger of the models for eukaryotic and bacterial ferritin into a common mechanism of Fe II oxidation in which the conserved tyrosine acts as a single‐electron molecular capacitor to facilitate oxidation of Fe II .