Apolar distal pocket mutants of yeast cytochrome c peroxidase: hydrogen peroxide reactivity and cyanide binding of the TriAla, TriVal, and TriLeu variants.

ABSTRACT: Three yeast cytochrome c peroxidase (CcP) variants with apolar distal heme pockets have been constructed. The CcP variants have Arg48, Trp51, and His52 mutated to either all alanines, CcP(triAla), all valines, CcP(triVal), or all leucines, CcP(triLeu). The triple mutants have detectable enzymatic activity at pH 6 but the activity is less than 0.02% that of wild-type CcP. The activity loss is primarily due to the decreased rate of reaction between the triple mutants and H(2)O(2) compared to wild-type CcP. Spectroscopic properties and cyanide binding characteristics of the triple mutants have been investigated over the pH stability region of CcP, pH 4 to 8. The absorption spectra indicate that the CcP triple mutants have hemes that are predominantly five-coordinate, high-spin at pH 5 and six

SUBMITTER: Bidwai AK 

PROVIDER: S-EPMC3530626 | biostudies-literature | 2013 Jan

REPOSITORIES: biostudies-literature