Electron paramagnetic resonance properties of liver fluke (Dicrocoelium dendriticum) nitrosyl hemoglobin

Alessandro Desideri, U. Thomas Meier, Kaspar H. Winterhalter, Ernesto E. Di Iorio

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Abstract

The electron paramagnetic resonance properties of the nitric oxide derivative of liver fluke (Dicrocoelium dendriticum) hemoglobin (DD-Hb) have been investigated in the pH range from 4.8 to 7.8. In the neutral and alkaline regions the spectra have a rhombic shape, with gx=2.09, gy=1.99 and gz=2.009, and a triplet hyperfine structure of 2.2 mT, due to the nitrogen of the bound NO molecule, in the center resonance. No superhyperfine lines in the gz region, related to the interaction of the iron with the proximal histidine, are detected, suggesting a large distance between the metal and the Nε{lunate} of the imidazole. By lowering the pH the EPR spectrum undergoes a reversible change showing a 3-line pattern in the high-field region. Such a spectrum is fully formed at pH 4.8 and is interpreted in terms of a dissociation of the proximal histidine from the heme iron.

Original languageEnglish (US)
Pages (from-to)378-380
Number of pages3
JournalFEBS Letters
Volume166
Issue number2
DOIs
Publication statusPublished - Jan 30 1984
Externally publishedYes

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Keywords

  • Dicrocoelium dendriticum
  • Distal histidine
  • ERP
  • Hemoglobin
  • Liver fluke

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology
  • Genetics
  • Cell Biology

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