Crystal structure of guaiacol and phenol bound to a heme peroxidase.

Journal article

Guaiacol is a universal substrate for all peroxidases, and its use in a simple colorimetric assay has wide applications. However, its exact binding location has never been defined. Here we report the crystal structures of guaiacol bound to cytochrome c peroxidase (CcP). A related structure with phenol bound is also presented. The CcP-guaiacol and CcP-phenol crystal structures show that both guaiacol and phenol bind at sites distinct from the cytochrome c binding site and from the δ-heme edge, which is known to be the binding site for other substrates. Although neither guaiacol nor phenol is seen bound at the δ-heme edge in the crystal structures, inhibition data and mutagenesis strongly suggest that the catalytic binding site for aromatic compounds is the δ-heme edge in CcP. The functional implications of these observations are discussed in terms of our existing understanding of substrate binding in peroxidases [Gumiero A et al. (2010) Arch Biochem Biophys 500, 13-20].

Authors: Murphy, E; Metcalfe, C; Nnamchi, C; Moody, P; Raven, E

• Publication status: Published
• Journal: FEBS journal
• Volume: 279
• Issue: 9
• Pages: 1632-1639
• Publication date: 2012-05-01
• DOI: 10.1111/j.1742-4658.2011.08425.x
• EISSN: 1742-4658
• ISSN: 1742-464X
• Language: English
• Keywords: Crystallography, X-Ray; Guaiacol; Cytochrome-c Peroxidase; Mutagenesis, Site-Directed; Binding Sites; Phenol