Resonance Raman spectroscopy study of change of iron spin state in horseradish peroxidase C induced by removal of calcium
| Autor: | Judit Fidy, Krisztián Szigeti, Qing Huang, Reinhard Schweitzer-Stenner, Monique Laberge |
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| Rok vydání: | 2003 |
| Předmět: |
Models
Molecular Hemeprotein Spin states Protein Conformation Ultraviolet Rays Iron Resonance Raman spectroscopy Biophysics Analytical chemistry Heme Spectrum Analysis Raman Photochemistry Biochemistry Horseradish peroxidase Biomaterials symbols.namesake medicine Horseradish Peroxidase Quantitative Biology::Biomolecules Binding Sites Quenching (fluorescence) Molecular Structure biology Chemistry Quantitative Biology::Molecular Networks Organic Chemistry General Medicine biology.protein symbols Ferric Calcium Raman spectroscopy Peroxidase medicine.drug |
| Zdroj: | Biopolymers. 72:241-248 |
| ISSN: | 1097-0282 0006-3525 |
| DOI: | 10.1002/bip.10417 |
| Popis: | Resonance Raman spectroscopy is used to probe the effect of calcium depletion on the heme group of horseradish peroxidase C at pH 8. Polarized Raman spectra are recorded with an argon ion laser at eight different wavelengths to provide a sound database for a reliable spectral decomposition. Upon calcium depletion, the spectrum is indicative of a predominantly pentacoordinated high spin state of the heme iron coexisting with small fractions of hexacoordinated high and low spin states. The dominant quantum mixed spin state of native ferric horseradish peroxidase, which is characteristic for class III peroxidases, is not detectable in the spectrum of the enzyme with partial distal Ca(2+) depletion. The quenching of the quantum mixed spin state and the predominance of the pentacoordinated high spin state are likely to arise from distortions induced by distal calcium depletion, which translates into a weaker Fe-N(epsilon)(His) bond and a more tilted imidazole. A correlation is proposed between the lower enzyme activity and the elimination of the pentacoordinated quantum mixed state upon Ca(2+) depletion. |
| Databáze: | OpenAIRE |
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