Theoretica chimica acta

, Volume 36, Issue 1, pp 67–76

Mössbauer and molecular orbital study of the myoglobin-CO complex


  • Alfred Trautwein
    • Angewandte PhysikUniversität des Saarlandes
  • Yutaka Maeda
    • Angewandte PhysikUniversität des Saarlandes
  • Frank E. Harris
    • Department of PhysicsUniversity of Utah
  • Helmuth Formanek
    • Botanisches InstitutUniversität München

DOI: 10.1007/BF00549150

Cite this article as:
Trautwein, A., Maeda, Y., Harris, F.E. et al. Theoret. Chim. Acta (1974) 36: 67. doi:10.1007/BF00549150


Experimental Mössbauer spectra of the Fe57-enriched CO complex of sperm whale myoglobin (MbCO) at T= 4.2 K with and without applied magnetic field (H⊥γ) were measured to derive the sign of the electric field gradient (EFG), the quadrupole splitting ΔEQ, and the isomer shift δ of the heme iron. We find a positive EFG, δEQ = 0.363 mm/sec, and δ + 0.266 mm/sec. Molecular orbital calculations were carried out to obtain theoretical estimates of EFG and ΔEQ for several steric arrangements of the CO ligand relative to the heme group. Our results are most consistent with the conclusion that the iron is situated in the heme plane, and that a bent geometry with a Fe-C-O angle of about 135 ° is more favorable than a more symmetric structure with a linear Fe-C-O geometry.

Key words

Mössbauer spectraMyoglobin-CO complex

Copyright information

© Springer-Verlag 1974