Active site structure of the catalase-peroxidases from Mycobacterium tuberculosis and Escherichia coli by extended X-ray absorption fine structure analysis

Linda Powers, Alex Hillar, Peter C. Loewen

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

The catalase-peroxidase encoded by katG of Mycobacterium tuberculosis is a more effective activator of the antibiotic isoniazid than is the equivalent enzyme from Escherichia coli. The environment of the heme iron was investigated using X-ray absorption spectroscopy to determine if differences in this region were associated with the differences in reactivity. The variation in the distal side Fe-ligand distances between the two enzymes was the same within experimental error indicating that it was not the heme iron environment that produced the differences in reactivity. Analysis of variants of the E. coli catalase-peroxidase containing changes in active site residues Arg102 and His106 revealed small differences in Fe-water ligand distance including a shorter distance for the His106Tyr variant. The Arg102Leu variant was 5-coordinate, but His106Cys and Arg102Cys variants showed no changes within experimental error. These results are compared with those reported for other peroxidases.

Original languageEnglish (US)
Pages (from-to)44-54
Number of pages11
JournalBiochimica et Biophysica Acta - Protein Structure and Molecular Enzymology
Volume1546
Issue number1
DOIs
StatePublished - Mar 9 2001
Externally publishedYes

Keywords

  • Catalase-peroxidase active site
  • EXFAS
  • Mycobacterium tuberculosis

ASJC Scopus subject areas

  • Biophysics
  • Structural Biology
  • Biochemistry
  • Molecular Biology

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