Dynamic structural disorder of the FeO2 moiety in oxymyoglobin studied by nuclear resonant forward scattering of synchrotron radiation

Oxy- as well as deoxymyoglobin exhibit a pronounced temperature dependence of the quadrupole splitting of the heme iron as detected by conventional Mössbauer spectroscopy. With nuclear resonant forward scattering (NFS) of synchrotron radiation, which can be viewed as Mössbauer spectroscopy in the ti...

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Bibliographic Details
Published in:European biophysics journal 2002-10, Vol.31 (6), p.478-484
Main Authors: Herta, C, Winkler, H, Benda, R, Haas, M, Trautwein, A X
Format: Article
Language:English
Subjects:
Biophysics
Electrochemistry - methods
Hemoglobins - chemistry
Iron
Iron - chemistry
Molecular biology
Molecular Conformation
Myoglobin - chemistry
Oxygen - chemistry
Proteins
Radiation
Scattering
Scattering, Radiation
Spectroscopy
Spectroscopy, Mossbauer - methods
Spectrum analysis
Spectrum Analysis - methods
Stochastic Processes
Temperature
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Summary:Oxy- as well as deoxymyoglobin exhibit a pronounced temperature dependence of the quadrupole splitting of the heme iron as detected by conventional Mössbauer spectroscopy. With nuclear resonant forward scattering (NFS) of synchrotron radiation, which can be viewed as Mössbauer spectroscopy in the time domain, it is shown that this spectroscopic behavior, although it is phenomenologically similar in the two cases, is based on completely different physical mechanisms. It is demonstrated that stochastic fluctuations of the iron electric field gradient in MbO(2), which are due to the dynamic structural disorder of the FeO(2) moiety, are the reason for the temperature-dependent alterations of the coherent quantum beat pattern in the NFS spectra of MbO(2), in contrast to deoxyMb where transitions between orbital states of iron take place. This subtle spectroscopic difference cannot be inferred from conventional Mössbauer spectroscopy.
ISSN:0175-7571
1432-1017
DOI:10.1007/s00249-002-0237-z