JBIC Journal of Biological Inorganic Chemistry

, Volume 12, Issue 4, pp 509–525

Spectroscopic description of an unusual protonated ferryl species in the catalase from Proteus mirabilis and density functional theory calculations on related models. Consequences for the ferryl protonation state in catalase, peroxidase and chloroperoxidase

  • O. Horner
  • J-M. Mouesca
  • P. L. Solari
  • M. Orio
  • J-L. Oddou
  • P. Bonville
  • H. M. Jouve
Original Paper

DOI: 10.1007/s00775-006-0203-9

Cite this article as:
Horner, O., Mouesca, JM., Solari, P.L. et al. J Biol Inorg Chem (2007) 12: 509. doi:10.1007/s00775-006-0203-9


The catalase from Proteus mirabilis peroxide-resistant bacteria is one of the most efficient heme-containing catalases. It forms a relatively stable compound II. We were able to prepare samples of compound II from P. mirabilis catalase enriched in 57Fe and to study them by spectroscopic methods. Two different forms of compound II, namely, low-pH compound II (LpH II) and high-pH compound II (HpH II), have been characterized by Mössbauer, extended X-ray absorption fine structure (EXAFS) and UV-vis absorption spectroscopies. The proportions of the two forms are pH-dependent and the pH conversion between HpH II and LpH II is irreversible. Considering (1) the Mössbauer parameters evaluated for four related models by density functional theory methods, (2) the existence of two different Fe–Oferryl bond lengths (1.80 and 1.66 Å) compatible with our EXAFS data and (3) the pH dependence of the α band to β band intensity ratio in the absorption spectra, we attribute the LpH II compound to a protonated ferryl FeIV–OH complex (Fe–O approximately 1.80 Å), whereas the HpH II compound corresponds to the classic ferryl FeIV=O complex (Fe=O approximately 1.66 Å). The large quadrupole splitting value of LpH II (measured 2.29 mm s−1 vs. computed 2.15 mm s−1) compared with that of HpH II (measured 1.47 mm s−1 vs. computed 1.46 mm s−1) reflects the protonation of the ferryl group. The relevancy and involvement of such (FeIV=O/FeIV–OH) species in the reactivity of catalase, peroxidase and chloroperoxidase are discussed.


Catalase compound IIProtonated ferryl speciesMössbauer spectroscopyDensity functional theory calculationsExtended X-ray absorption fine structure





Density functional theory




Electron paramagnetic resonance


Extended X-ray absorption fine structure


High-pH Proteus mirabilis catalase compound II


Horseradish peroxidase


Low-pH Proteus mirabilis catalase compound II


Micrococcus lysodeikticus catalase


Molecular orbital


Proteus mirabilis catalase





Supplementary material

775_2006_203_MOESM1_ESM.doc (688 kb)
Supplementary material: Reference UV-visible spectra of PMC resting state, compound I and compound II (Fig. S1); Mössbauer spectra of as-isolated 57Fe catalase from P. mirabilis at 4.2 K in a magnetic field of 50 mT and 7.0 T applied parallel to the γ-beam (Fig. S2); Mössbauer spectrum of compound I in 57Fe catalase from P. mirabilis at 40 K in a magnetic field of 3T applied parallel to the γ-beam (Fig. S3); Mössbauer spectrum of compound II in 57Fe catalase from P. mirabilis at 150 K in a magnetic field of 7.0 T applied parallel to the γ-beam (Fig. S4);comparison between the visible absorption spectra of compound II samples used for EXAFS and Mössbauer measurements (Fig. S5); experimental EXAFS of PMC compound II from P. mirabilis at pH 8.0 with results of the EXAFS analysis considering two distinct iron–oxo contributions (Fig. S6); projection of the minimization function on the (R–Fe=O, R–Fe–OH) plane, i.e. contour plot (regions enclosed by squares correspond to the 95% confidence interval) (Fig. S7); linear correlation between the computed quadrupole splitting ΔEQ and the computed electronic density at the iron nucleus ρ(Fe), by using all six FeIV=O models of compound II at high pH and four possible FeIV–OH models of compound II at low pH (Figure S8); optimized coordinates for the models 1, 1ter, 2, 2ter, 3, 3bis and 4 (Table S1 a–g); structural parameters and quadrupole splitting in case of the alternative protonation of the axial Tyrosine residue (here without cation) (Table S2); repartition of the iron spin population (%) among the d atomic orbitals for the models 1 to 4. Summation per spin (∑dαβ) and total iron spin populations (∑dα−∑dβ) (Table S3); mononuclear iron biomolecules and complexes used for establishing the linear correlation between experimentally measured isomer shifts at 4.2 K and experimentally measured quadrupole splitting at 4.2 K (Table S4). (DOC 687 kb)

Copyright information

© SBIC 2007

Authors and Affiliations

  • O. Horner
    • 1
  • J-M. Mouesca
    • 2
  • P. L. Solari
    • 3
    • 6
  • M. Orio
    • 2
  • J-L. Oddou
    • 1
  • P. Bonville
    • 4
  • H. M. Jouve
    • 5
  1. 1.Laboratoire de Physicochimie des Métaux en BiologieUMR CEA/CNRS/Université Joseph Fourier 5155Grenoble Cedex 9France
  2. 2.Département de Recherche Fondamentale sur la Matière Condensée, Laboratoire de Résonances Magnétiques, Service de Chimie Inorganique et BiologiqueUMR CEA/Université Joseph Fourier E3Grenoble Cedex 9France
  3. 3.European Synchrotron Radiation FacilityGrenobleFrance
  4. 4.Département de Recherches sur l’Etat CondenséService de Physique de l’Etat CondenséGif-sur-Yvette CedexFrance
  5. 5.Institut de Biologie Structurale Jean-Pierre EbelUMR CEA/CNRS/Université Joseph Fourier 5075Grenoble Cedex 1France
  6. 6.Synchrotron SoleilGif-sur-Yvette CedexFrance