title: Structure of Thermobifida fusca DyP-type peroxidase and activity towards Kraft lignin and lignin model compounds.
abstract: A Dyp-type peroxidase enzyme from thermophilic cellulose degrader Thermobifida fusca (TfuDyP) was investigated for catalytic ability towards lignin oxidation. TfuDyP was characterised kinetically against a range of phenolic substrates, and a compound I reaction intermediate was observed via pre-steady state kinetic analysis at λmax 404 nm. TfuDyP showed reactivity towards Kraft lignin, and was found to oxidise a β-aryl ether lignin model compound, forming an oxidised dimer. A crystal structure of TfuDyP was determined, to 1.8 Å resolution, which was found to contain a diatomic oxygen ligand bound to the heme centre, positioned close to active site residues Asp-203 and Arg-315. The structure contains two channels providing access to the heme cofactor for organic substrates and hydrogen peroxide. Site-directed mutant D203A showed no activity towards phenolic substrates, but reduced activity towards ABTS, while mutant R315Q showed no activity towards phenolic substrates, nor ABTS.
authors.affiliation: Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
authors.forename: Rahman
authors.initials: R
authors.lastname: Rahmanpour
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
authors.forename: Dean
authors.initials: D
authors.lastname: Rea
authors.affiliation: Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
authors.forename: Shirin
authors.initials: S
authors.lastname: Jamshidi
authors.affiliation: School of Life Sciences, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK.
authors.forename: Vilmos
authors.initials: V
authors.lastname: Fülöp
authors.affiliation: Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL, UK. Electronic address: T.D.Bugg@warwick.ac.uk.
authors.forename: Timothy D H
authors.initials: TD
authors.lastname: Bugg
mesh_terms: D039903:Actinobacteria / Q000201:enzymology*; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D007700:Kinetics; D008031:Lignin / Q000378:metabolism*; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D010084:Oxidation-Reduction; D009195:Peroxidase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
chemical_list: C076151:Kraft lignin; D008031:Lignin; D009195:Peroxidase
keywords: Dye decolorizing peroxidase; Dyp; Lignin oxidation; Protein crystallography