Search

Your search keyword '"VA, veratryl alcohol"' showing total 2 results
Start Over Descriptor "VA, veratryl alcohol"
2 results on '"VA, veratryl alcohol"'

1. Reactions of “hybrid” Mn-peroxidase of the white rot fungus Panus tigrinus with benzylic alcohols in the presence of mediators

Author

Lisov, Alexander, Leontievsky, Alexey, Golovleva, Ludmila, and Evans, Christine

Subjects
*PEROXIDASE, *OXIDOREDUCTASES, *METALLOENZYMES, *BENZYLAMINOPURINE
Abstract

“Hybrid” Mn-peroxidase (hMnP) isolated from the white rot fungus Panus tigrinus 8/18 was studied with respect to its reactions with veratryl alcohol in the presence of typical laccase mediators in the reaction mixture. Eight compounds were tested as potential mediators in this reaction and only 1-hydroxybenzotriazole (HBT) and 3-hydroxy-1,2,3-benzotriazin-4(3H)-one (HBTO) were found to be effective. Up to 99% of 1M veratryl alcohol was oxidized with formation of veratraldehyde as a reaction product over 24h depending on the buffer system used. Except for veratryl alcohol, anisyl alcohol but not benzyl alcohol was oxidized in this reaction. Reactions with the participance of mediators were not catalytic, and the mediators were consumed during reaction with formation of dehydroxylated derivatives. Reactions with both HBT and HBTO resulted in temporal inactivation of hMnP. Kinetics of hMnP inactivation revealed it to be a pseudo-third order reaction. Investigation of the transformation of the absorption spectra of hMnP redox cycle intermediates in the presence of HBT or HBTO showed that the most likely reason of hMnP inactivation was its interaction with non-oxidized mediators. [Copyright &y& Elsevier]

Published
2004
Full Text
View/download PDF

2. Catalytic surface radical in dye-decolorizing peroxidase: A computational, spectroscopic and directed mutagenesis study

Author

Ángel T. Martínez, Rebecca Pogni, Francisco J. Medrano, Marina Cañellas, Dolores Linde, Victor Guallar, Verónica Sáez-Jiménez, Francisco J. Ruiz-Dueñas, Adalgisa Sinicropi, Antonio A. Romero, Cristina Coscolín, Maria Camilla Baratto, Fátima Lucas, and Barcelona Supercomputing Center

Subjects
Models, Molecular, Protein Conformation, ABTS, 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid), VP, versatile peroxidase, dye-decolorizing peroxidase, site-directed mutagenesis, EPR spectroscopy, molecular docking, QM/MM, catalytic protein radicals, QM, quantum mechanics, VA, veratryl alcohol, Multifrequency EPR, Biochemistry, Protein structure, catalytic protein radicals, Auricularia auricula-judae, NBS, N-bromosuccinimide, Coloring Agents, Site-directed mutagenesis, Dye decolorizing peroxidase, chemistry.chemical_classification, Fungal protein, biology, Chemistry, Enginyeria mecànica::Impacte ambiental [Àrees temàtiques de la UPC], Tryptophan, PELE, Protein Energy Landscape Exploration, Recombinant Proteins, hfcc, hyperfine coupling constant, Molecular Docking Simulation, Peroxidases, catalytic protein radical, Molecular docking, site-directed mutagenesis, Oxidation-Reduction, Research Article, EPR spectroscopy, RB19, Reactive Blue 19, Peroxidase, Hemeproteins, Free Radicals, Surface Properties, Stereochemistry, LRET, long-range electron transfer, DyP, dye-decolorizing peroxidase, Molecular Dynamics Simulation, QM/MM, Fungal Proteins, RB5, Reactive Black 5, Oxidoreductase, dye-decolorizing peroxidase, Enzyme kinetics, LiP, lignin peroxidase, Catalytic protein radicals, Molecular Biology, Dye-decolorizing peroxidase, Binding Sites, Basidiomycota, Protein, DMP, 2,6-dimethoxyphenol, MM, molecular mechanics, molecular docking, Cell Biology, WT, wild-type, TNM, tetranitromethane, Amino Acid Substitution, Biocatalysis, Mutagenesis, Site-Directed, biology.protein, Tyrosine, Mutant Proteins, Proteïnes
Abstract

Dye-decolorizing peroxidase (DyP) of Auricularia auricula-judae has been expressed in Escherichia coli as a representative of a new DyP family, and subjected to mutagenic, spectroscopic, crystallographic and computational studies. The crystal structure of DyP shows a buried haem cofactor, and surface tryptophan and tyrosine residues potentially involved in long-range electron transfer from bulky dyes. Simulations using PELE (Protein Energy Landscape Exploration) software provided several binding-energy optima for the anthraquinone-type RB19 (Reactive Blue 19) near the above aromatic residues and the haem access-channel. Subsequent QM/MM (quantum mechanics/molecular mechanics) calculations showed a higher tendency of Trp-377 than other exposed haem-neighbouring residues to harbour a catalytic protein radical, and identified the electron-transfer pathway. The existence of such a radical in H2O2-activated DyP was shown by low-temperature EPR, being identified as a mixed tryptophanyl/tyrosyl radical in multifrequency experiments. The signal was dominated by the Trp-377 neutral radical contribution, which disappeared in the W377S variant, and included a tyrosyl contribution assigned to Tyr-337 after analysing the W377S spectra. Kinetics of substrate oxidation by DyP suggests the existence of high- and low-turnover sites. The high-turnover site for oxidation of RB19 (kcat> 200 s−1) and other DyP substrates was assigned to Trp-377 since it was absent from the W377S variant. The low-turnover site/s (RB19 kcat ~20 s−1) could correspond to the haem access-channel, since activity was decreased when the haem channel was occluded by the G169L mutation. If a tyrosine residue is also involved, it will be different from Tyr-337 since all activities are largely unaffected in the Y337S variant., We demonstrate that an exposed tryptophan is responsible for high-turnover oxidation by DyP, a representative of a new protein superfamily. Long-range electron transfer from surface tryptophan residues forming radicals appears as a general mechanism for peroxidase oxidation of bulky substrates.

Published
2015

Catalog

Books, media, physical & digital resources
See catalog results