A new role for heme, facilitating release of iron from the bacterioferritin iron biomineral

Yasmin, Samina, Andrews, Simon C., Moore, Geoffrey R. and Le Brun, Nick E. ORCID: https://orcid.org/0000-0001-9780-4061 (2011) A new role for heme, facilitating release of iron from the bacterioferritin iron biomineral. The Journal of Biological Chemistry, 286 (5). pp. 3473-3483. ISSN 1083-351X

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Abstract

Bacterioferritin (BFR) from Escherichia coli is a member of the ferritin family of iron storage proteins and has the capacity to store very large amounts of iron as an Fe3+ mineral inside its central cavity. The ability of organisms to tap into their cellular stores in times of iron deprivation requires that iron must be released from ferritin mineral stores. Currently, relatively little is known about the mechanisms by which this occurs, particularly in prokaryotic ferritins. Here we show that the bis-Met-coordinated heme groups of E. coli BFR, which are not found in other members of the ferritin family, play an important role in iron release from the BFR iron biomineral: kinetic iron release experiments revealed that the transfer of electrons into the internal cavity is the rate-limiting step of the release reaction and that the rate and extent of iron release were significantly increased in the presence of heme. Despite previous reports that a high affinity Fe2+ chelator is required for iron release, we show that a large proportion of BFR core iron is released in the absence of such a chelator and further that chelators are not passive participants in iron release reactions. Finally, we show that the catalytic ferroxidase center, which is central to the mechanism of mineralization, is not involved in iron release; thus, core mineralization and release processes utilize distinct pathways.

Item Type:	Article
Faculty \ School:	Faculty of Science > School of Chemistry (former - to 2024)
UEA Research Groups:	Faculty of Science > Research Groups > Biophysical Chemistry (former - to 2017) Faculty of Science > Research Groups > Chemistry of Life Processes Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry Faculty of Science > Research Groups > Centre for Ocean and Atmospheric Sciences
Depositing User:	Rachel Smith
Date Deposited:	23 Mar 2011 10:57
Last Modified:	24 Sep 2024 09:00
URI:	https://ueaeprints.uea.ac.uk/id/eprint/26962
DOI:	10.1074/jbc.M110.175034

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