Reactivity of manganese peroxidase: Site-directed mutagenesis of residues in proximity to the porphyrin ring

Katia Ambert-Balay, Mike Dougherty, Ming Tien

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The purpose of this study was to determine the effect of heme pocket hydrophobicity on the reactivity of manganese peroxidase. Residues within 5 Å of the heme active site were identified. From this group, Leu169 and Ser172 were selected and mutated to Phe and Ala, respectively. The mutant proteins were then characterized by steady-state kinetics. Whereas the Leu169Phe mutation had little, if any, effect on activity, the Ser172Ala mutation decreased k(cat) and also the specificity constant (k(cat)/K(m)) for Mn2+, but not H2O2. Transient-state studies indicated that the mutation affected only the reactions of compound II. These results indicate that compound II is the most sensitive to changes in the heme environment. (C) 2000 Academic Press.

Original languageEnglish (US)
Pages (from-to)89-94
Number of pages6
JournalArchives of Biochemistry and Biophysics
Volume382
Issue number1
DOIs
StatePublished - Oct 1 2000

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manganese peroxidase
Mutagenesis
Porphyrins
Site-Directed Mutagenesis
Heme
Mutation
Mutant Proteins
Hydrophobicity
Hydrophobic and Hydrophilic Interactions
Catalytic Domain
Kinetics

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology

Cite this

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Reactivity of manganese peroxidase : Site-directed mutagenesis of residues in proximity to the porphyrin ring. / Ambert-Balay, Katia; Dougherty, Mike; Tien, Ming.

In: Archives of Biochemistry and Biophysics, Vol. 382, No. 1, 01.10.2000, p. 89-94.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Reactivity of manganese peroxidase

T2 - Site-directed mutagenesis of residues in proximity to the porphyrin ring

AU - Ambert-Balay, Katia

AU - Dougherty, Mike

AU - Tien, Ming

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AB - The purpose of this study was to determine the effect of heme pocket hydrophobicity on the reactivity of manganese peroxidase. Residues within 5 Å of the heme active site were identified. From this group, Leu169 and Ser172 were selected and mutated to Phe and Ala, respectively. The mutant proteins were then characterized by steady-state kinetics. Whereas the Leu169Phe mutation had little, if any, effect on activity, the Ser172Ala mutation decreased k(cat) and also the specificity constant (k(cat)/K(m)) for Mn2+, but not H2O2. Transient-state studies indicated that the mutation affected only the reactions of compound II. These results indicate that compound II is the most sensitive to changes in the heme environment. (C) 2000 Academic Press.

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