Second coordination sphere effects on the mechanistic pathways for dioxygen activation by a ferritin: involvement of a Tyr radical and the identification of a cation binding site

Yeh, Chieh-Chih George, Mokkawes, Thirakorn, Bradley, Justin M., Le Brun, Nick E. ORCID: https://orcid.org/0000-0001-9780-4061 and de Visser, Sam P. (2022) Second coordination sphere effects on the mechanistic pathways for dioxygen activation by a ferritin: involvement of a Tyr radical and the identification of a cation binding site. ChemBioChem, 23 (13). ISSN 1439-4227

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Abstract

Ferritins are ubiquitous diiron enzymes involved in iron(II) detoxification and oxidative stress responses and can act as metabolic iron stores. The overall reaction mechanisms of ferritin enzymes are still unclear, particularly concerning the role of the conserved, near catalytic center Tyr residue. Thus, we carried out a computational study of a ferritin using a large cluster model of well over 300 atoms including its first- and second-coordination sphere. The calculations reveal important insight into the structure and reactivity of ferritins. Specifically, the active site Tyr residue delivers a proton and electron in the catalytic cycle prior to iron(II) oxidation. In addition, the calculations highlight a likely cation binding site at Asp65, which through long-range electrostatic interactions, influences the electronic configuration and charge distributions of the metal center. The results are consistent with experimental observations but reveal novel detail of early mechanistic steps that lead to an unusual mixed-valent iron(III)-iron(II) center.

Item Type:	Article
Additional Information:	Acknowledgements: This work was supported by BBSRC grant BB/R002363/1 to NELB and JMB. Data sharing statement: All relevant data are presented in the main paper or in the Supporting Information, and are available from the authors upon reasonable request.
Faculty \ School:	Faculty of Science > School of Chemistry
UEA Research Groups:	Faculty of Science > Research Groups > Chemistry of Life Processes Faculty of Science > Research Centres > Centre for Molecular and Structural Biochemistry
Depositing User:	LivePure Connector
Date Deposited:	24 May 2022 14:58
Last Modified:	22 Oct 2022 18:32
URI:	https://ueaeprints.uea.ac.uk/id/eprint/85076
DOI:	10.1002/cbic.202200257

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