Dehaloperoxidase (DHP) from the marine worm Amphitrite ornata is a globin exhibiting significant peroxidase activity. The active site of this bifunctional enzyme is a heme center, which is coordinated by a histidine residue in the proximal position and exhibits an internal distal cavity. Purified recombinant 57Fe-DHP samples were studied with M�ssbauer spectroscopy in order to obtain a characterization of the enzyme in the resting state and throughout its catalytic cycle. Chemical reduction with ascorbate yielded the oxy-ferrous state, which exhibits a M�ssbauer spectrum typical of a low-spin Fe(II) heme, analogous to oxy-myoglobin. Different aspects of the M�ssbauer spectra show similarities with myoglobin, but also with peroxidases. This study will ascertain the spin and oxidation states of the iron in the several catalytic states and will draw comparisons between DHP and other heme proteins, based on the M�ssbauer spectroscopic data.  DHP dehalogenates 2,4,6-tribromophenol, which, like other halophenols of various origins, is toxic. Thus, elucidation of the electronic structure and mechanism is of this peroxidase is of general interest for environmental remediation.

M�ssbauer spectroscopic studies of the enzyme dehaloperoxidase from <i>Amphitrite ornata</i>

247th National Meeting (2014)

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M�ssbauer spectroscopic studies of the enzyme dehaloperoxidase from Amphitrite ornata