Download MendeleyImproved Manganese-Oxidizing Activity of DypB, a Peroxidase from a Lignolytic Bacterium.
Singh, R., Grigg, J.C., Qin, W., Kadla, J.F., Murphy, M.E., Eltis, L.D.(2013) ACS Chem Biol 8: 700-706
- PubMed: 23305326
- DOI: https://doi.org/10.1021/cb300608x
- Primary Citation of Related Structures:
4HOV - PubMed Abstract:
DypB, a dye-decolorizing peroxidase from the lignolytic soil bacterium Rhodococcus jostii RHA1, catalyzes the peroxide-dependent oxidation of divalent manganese (Mn(2+)), albeit less efficiently than fungal manganese peroxidases. Substitution of Asn246, a distal heme residue, with alanine increased the enzyme's apparent k(cat) and k(cat)/K(m) values for Mn(2+) by 80- and 15-fold, respectively. A 2.2 Å resolution X-ray crystal structure of the N246A variant revealed the Mn(2+) to be bound within a pocket of acidic residues at the heme edge, reminiscent of the binding site in fungal manganese peroxidase and very different from that of another bacterial Mn(2+)-oxidizing peroxidase. The first coordination sphere was entirely composed of solvent, consistent with the variant's high K(m) for Mn(2+) (17 ± 2 mM). N246A catalyzed the manganese-dependent transformation of hard wood kraft lignin and its solvent-extracted fractions. Two of the major degradation products were identified as 2,6-dimethoxybenzoquinone and 4-hydroxy-3,5-dimethoxybenzaldehyde, respectively. These results highlight the potential of bacterial enzymes as biocatalysts to transform lignin.
Organizational Affiliation:
Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada.
