title: The toolbox of Auricularia auricula-judae dye-decolorizing peroxidase - Identification of three new potential substrate-interaction sites.
abstract: Dye-decolorizing peroxidases (DyPs) such as AauDyPI from the fungus Auricularia auricula-judae are able to oxidize substrates of different kinds and sizes. A crystal structure of an AauDyPI-imidazole complex gives insight into the binding patterns of organic molecules within the heme cavity of a DyP. Several small N-containing heterocyclic aromatics are shown to bind in the AauDyPI heme cavity, hinting to susceptibility of DyPs to azole-based inhibitors similar to cytochromes P450. Imidazole is confirmed as a competitive inhibitor with regard to peroxide binding. In contrast, bulky substrates such as anthraquinone dyes are converted at the enzyme surface. In the crystal structure a substrate analog, 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES), binds to a tyrosine-rich hollow harboring Y25, Y147, and Y337. Spin trapping with a nitric oxide donor uncovers Y229 as an additional tyrosine-based radical center in AauDyPI. Multi-frequency EPR spectroscopy further reveals the presence of at least one intermediate tryptophanyl radical center in activated AauDyPI with W377 as the most likely candidate.
authors.affiliation: Institute of Organic Chemistry, University of Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
authors.forename: Eric
authors.initials: E
authors.lastname: Strittmatter
authors.affiliation: Institute of Physical Chemistry, University of Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Serrer
authors.affiliation: Department of Bio- and Environmental Sciences, TU Dresden - International Institute Zittau, 02763 Zittau, Germany.
authors.forename: Christiane
authors.initials: C
authors.lastname: Liers
authors.affiliation: Department of Bio- and Environmental Sciences, TU Dresden - International Institute Zittau, 02763 Zittau, Germany.
authors.forename: René
authors.initials: R
authors.lastname: Ullrich
authors.affiliation: Department of Bio- and Environmental Sciences, TU Dresden - International Institute Zittau, 02763 Zittau, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Hofrichter
authors.affiliation: Institute of Organic Chemistry, University of Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
authors.forename: Klaus
authors.initials: K
authors.lastname: Piontek
authors.affiliation: Institute of Physical Chemistry, University of Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
authors.forename: Erik
authors.initials: E
authors.lastname: Schleicher
authors.affiliation: Institute of Organic Chemistry, University of Freiburg, Albertstrasse 21, 79104 Freiburg, Germany. Electronic address: dietmar.plattner@chemie.uni-freiburg.de.
authors.forename: Dietmar A
authors.initials: DA
authors.lastname: Plattner
mesh_terms: D001487:Basidiomycota / Q000201:enzymology*; D003116:Color; D004396:Coloring Agents / Q000378:metabolism*; D018360:Crystallography, X-Ray; D013058:Mass Spectrometry; D062105:Molecular Docking Simulation; D010544:Peroxidases / Q000737:chemistry / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity; D020349:Surface Plasmon Resonance
chemical_list: D004396:Coloring Agents; D010544:Peroxidases
keywords: Aspartate; Catalysis; Crystal structure; Dye-decolorizing peroxidases (DyPs); Electron paramagnetic resonance (EPR) spectroscopy; Heme; Mass spectrometry; Spin trapping; Tryptophan; Tyrosine