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Role of K(+) binding residues in stabilization of heme spin state of Leishmania major peroxidase.
- Source :
-
Biochimica et biophysica acta [Biochim Biophys Acta] 2012 Aug; Vol. 1824 (8), pp. 1002-7. Date of Electronic Publication: 2012 May 19. - Publication Year :
- 2012
-
Abstract
- The endogenous cation in peroxidases may contribute to the type of heme coordination. Here a series of ferric and ferrous derivatives of wild-type Leishmania major peroxidase (LmP) and of engineered K(+) site mutants of LmP, lacking potassium cation binding site, has been examined by electronic absorption spectroscopy at 25°C. Using UV-visible spectrophotometry, we show that the removal of K(+) binding site causes substantial changes in spin states of both the ferric and ferrous forms. The spectral changes are interpreted to be, most likely, due to the formation of a bis-histidine coordination structure in both the ferric and ferrous oxidation states at neutral pH 7.0. Stopped flow spectrophotometric techniques revealed that characteristics of Compound I were not observed in the K(+) site double mutants in the presence of H(2)O(2). Similarly electron donor oxidation rate was two orders less for the K(+) site double mutants compared to the wild type. These data show that K(+) functions in preserving the protein structure in the heme surroundings as well as the spin state of the heme iron, in favor of the enzymatically active form of LmP.<br /> (Copyright © 2012 Elsevier B.V. All rights reserved.)
- Subjects :
- Binding Sites
Heme metabolism
Hydrogen Peroxide metabolism
Hydrogen-Ion Concentration
Iron metabolism
Models, Molecular
Mutation
Oxidation-Reduction
Peroxidase genetics
Peroxidase metabolism
Potassium metabolism
Protozoan Proteins genetics
Protozoan Proteins metabolism
Heme chemistry
Leishmania enzymology
Peroxidase chemistry
Potassium chemistry
Protozoan Proteins chemistry
Subjects
Details
- Language :
- English
- ISSN :
- 0006-3002
- Volume :
- 1824
- Issue :
- 8
- Database :
- MEDLINE
- Journal :
- Biochimica et biophysica acta
- Publication Type :
- Academic Journal
- Accession number :
- 22617686
- Full Text :
- https://doi.org/10.1016/j.bbapap.2012.05.007