Determination of zero-field splitting and evidence for the presence of charge-transfer transitions in the Soret region of high-spin ferric hemoproteins obtained from an analysis of low-temperature magnetic circular dichroism

Oganesyan, Vasily S. ORCID: https://orcid.org/0000-0002-8738-1146 and Sharonov, Yuri A. (1998) Determination of zero-field splitting and evidence for the presence of charge-transfer transitions in the Soret region of high-spin ferric hemoproteins obtained from an analysis of low-temperature magnetic circular dichroism. Biochimica et Biophysica Acta - Protein Structure and Molecular Enzymology, 1429 (1). pp. 163-175. ISSN 0167-4838

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Abstract

Theoretical expressions for magnetic circular dichroism (MCD) of the porphyrin π→π*, spin-allowed charge transfer (CT) and spin-forbidden d-d or CT transitions in high-spin ferric heme are derived. The transitions can be discriminated by their MCD to absorption ratio and/or temperature dependence of MCD intensity. An analysis of the Soret MCD of fluoride complexes of myoglobin (Mb), hemoglobin (Hb) and horseradish peroxidase (HRP), recorded at temperatures from 290 down to 2 K, is given. It is shown that the Soret MCD of HRPF can be well described by overlapping of the π→π* transition with one spin-forbidden CT transition of an 6A1→4E type. In the case of MbF and HbF it is necessary to assume the presence in the Soret region of the second spin-forbidden CT transition, most probably of an 6A1→4A1 type. The parameters of transitions have been extracted from a non-linear least-squares fitting procedure. The best fit values of parameter D of the zero-field splitting of the ground manifold for HbF (6.1 cm-1) and MbF (6.4 cm-1) agree well with those obtained by other methods. The D value for HRPF (8.3 cm-1) is obtained for the first time.

Item Type: Article
Additional Information: Funding Information: We thank RFFI (grants 96-04-49076 and 96-15-98093) for financial support.
Uncontrolled Keywords: charge transfer transition,hemoprotein,high-spin ferric heme,magnetic circular dichroism,biophysics,structural biology,biochemistry,molecular biology ,/dk/atira/pure/subjectarea/asjc/1300/1304
Faculty \ School: Faculty of Science > School of Chemistry
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Depositing User: LivePure Connector
Date Deposited: 19 Jul 2022 17:30
Last Modified: 13 Aug 2022 02:25
URI: https://ueaeprints.uea.ac.uk/id/eprint/86650
DOI: 10.1016/S0167-4838(98)00228-3

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