Iron Normal Mode Dynamics in (Nitrosyl)iron(II)tetraphenylporphyrin from X-ray Nuclear Resonance Data
| Autor: | Earl W. Prohofsky, W. Robert Scheidt, Stephen M. Durbin, E. Ercan Alp, Brajesh K. Rai, Wolfgang Sturhahn, J. Timothy Sage, Graeme R. A. Wyllie |
|---|---|
| Rok vydání: | 2002 |
| Předmět: |
Hemeproteins
Hemeprotein Metalloporphyrins Iron Biophysics Analytical chemistry 02 engineering and technology 010402 general chemistry 01 natural sciences Biophysical Phenomena chemistry.chemical_compound Normal mode Atom Tetraphenylporphyrin Nuclear resonance vibrational spectroscopy Heme Physics::Biological Physics Quantitative Biology::Biomolecules Molecular Structure Myoglobin Spectrum Analysis X-Rays 021001 nanoscience & nanotechnology Porphyrin 0104 chemical sciences Crystallography Models Chemical chemistry Thermodynamics 0210 nano-technology Research Article |
| Zdroj: | Biophysical Journal. 82:2951-2963 |
| ISSN: | 0006-3495 |
| DOI: | 10.1016/s0006-3495(02)75636-1 |
| Popis: | The complete iron atom vibrational spectrum has been obtained by refinement of normal mode calculations to nuclear inelastic x-ray absorption data from (nitrosyl)iron(II)tetraphenylporphyrin, FeTPP(NO), a useful model for heme dynamics in myoglobin and other heme proteins. Nuclear resonance vibrational spectroscopy (NRVS) provides a direct measurement of the frequency and iron amplitude for all normal modes involving significant displacement of 57Fe. The NRVS measurements on isotopically enriched single crystals permit determination of heme in-plane and out-of-plane modes. Excellent agreement between the calculated and experimental values of frequency and iron amplitude for each mode is achieved by a force-field refinement. Significantly, we find that the presence of the phenyl groups and the NO ligand leads to substantial mixing of the porphyrin core modes. This first picture of the entire iron vibrational density of states for a porphyrin compound provides an improved model for the role of iron atom dynamics in the biological functioning of heme proteins. |
| Databáze: | OpenAIRE |
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