Hybridization of Modified-Heme Reconstitution and Distal Histidine Mutation to Functionalize Sperm Whale Myoglobin

Hideaki Sato, Takashi Hayashi, Tsutomu Ando, Yoshio Hisaeda, Takafumi Ueno, Yoshihito Watanabe

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    67 Citations (Scopus)

    Abstract

    To modulate the physiological function of a hemoprotein, most approaches have been demonstrated by site-directed mutagenesis. Replacement of the native heme with an artificial prosthetic group is another way to modify a hemoprotein. However, an alternate method, mutation or heme reconstitution, does not always demonstrate sufficient improvement compared with the native heme enzyme. In the present study, to convert a simple oxygen storage hemoprotein, myoglobin, into an active peroxidase, we applied both methods at the same time. The native heme of myoglobin was replaced with a chemically modified heme 2 having two aromatic rings at the heme-propionate termini. The constructed myoglobins were examined for 2-methoxyphenol (guaiacol) oxidation in the presence of H2O2. Compared with native myoglobin, rMb(H64D·2) showed a 430-fold higher kcat/Km value, which is significantly higher than that of cytochrome c peroxidase and only 3-fold less than that of horseradish peroxidase. In addition, myoglobin-catalyzed degradation of bisphenol A was examined by HPLC analysis. The rMb(H64D·2) showed drastic acceleration (>35-fold) of bisphenol A degradation compared with the native myoglobin. In this system, a highly oxidized heme reactive species is smoothly generated and a substrate is effectively bound in the heme pocket, while native myoglobin only reversibly binds dioxygen. The present results indicate that the combination of a modified-heme reconstitution and an amino acid mutation should offer interesting perspectives toward developing a useful biomolecule catalyst from a hemoprotein.

    Original languageEnglish
    Pages (from-to)436-437
    Number of pages2
    JournalJournal of the American Chemical Society
    Volume126
    Issue number2
    DOIs
    Publication statusPublished - Jan 21 2004

    All Science Journal Classification (ASJC) codes

    • Catalysis
    • Chemistry(all)
    • Biochemistry
    • Colloid and Surface Chemistry

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