Low-frequency EPR of ferrimyoglobin fluoride and ferrimyoglobin cyanide: a case study on the applicability of broadband analysis to high-spin hemoproteins and to HALS hemoproteins

Hagen, W.R.

doi:10.1007/s00775-022-01948-1

Low-frequency EPR of ferrimyoglobin fluoride and ferrimyoglobin cyanide

Title

Low-frequency EPR of ferrimyoglobin fluoride and ferrimyoglobin cyanide: a case study on the applicability of broadband analysis to high-spin hemoproteins and to HALS hemoproteins

Author

Hagen, W.R. (TU Delft BT/Biocatalysis)

Date

2022

Abstract

An EPR spectrometer has been developed that can be tuned to many frequencies in the range of ca 0.1–15 GHz. Applicability has been tested on ferrimyoglobin fluoride (MbF) and ferrimyoglobin cyanide (MbCN). MbF has a high-spin (S = 5/2) spectrum with ¹⁹F superhyperfine splitting that is only resolved in X-band along the heme normal. Low-frequency EPR also resolves the splitting in the heme plane. Measurement of linewidth as a function of frequency provides the basis for an analysis of inhomogeneous broadening in terms of g-strain, zero-field distribution, unresolved superhyperfine splittings and dipolar interaction. Rhombicity in the g tensor is found to be absent. MbCN (S = 1/2) has a highly anisotropic low spin (HALS) spectrum for which g_x cannot be determined unequivocally in X-band. Low-frequency EPR allows for measurement of the complete spectrum and determination of the g-tensor. Graphical abstract: [Figure not available: see fulltext.]

Subject

Broadband
EPR
HALS
Hemoprotein
Low-frequency
Myoglobin

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http://resolver.tudelft.nl/uuid:57f75049-447a-4f23-b85b-565ca8f83f17

DOI

https://doi.org/10.1007/s00775-022-01948-1

ISSN

0949-8257

Source

Journal of Biological Inorganic Chemistry, 27 (4-5), 497-507

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