Detection and Characterization of a Novel Copper‐Dependent Intermediate in a Lytic Polysaccharide Monooxygenase
| العنوان: | Detection and Characterization of a Novel Copper‐Dependent Intermediate in a Lytic Polysaccharide Monooxygenase |
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| المؤلفون: | Høgni Weihe, Benedikt M. Blossom, Bart van Oort, Roberta Croce, Ranjitha Singh, Claus Felby, Raushan Kumar Singh, Morten J. Bjerrum, Manish Kumar Tiwari, Poul Erik Jensen, David A. Russo |
| المصدر: | Chemistry – A European Journal. 26:454-463 |
| بيانات النشر: | Wiley, 2019. |
| سنة النشر: | 2019 |
| مصطلحات موضوعية: | Reaction mechanism, chemistry.chemical_element, 010402 general chemistry, Photochemistry, Polysaccharide, 01 natural sciences, Catalysis, Mixed Function Oxygenases, law.invention, chemistry.chemical_compound, law, Oxidizing agent, Reactivity (chemistry), Cellulose, Electron paramagnetic resonance, chemistry.chemical_classification, 010405 organic chemistry, Organic Chemistry, Electron Spin Resonance Spectroscopy, Hydrogen Peroxide, General Chemistry, Monooxygenase, Combinatorial chemistry, Copper, 0104 chemical sciences, Kinetics, chemistry, Biocatalysis, Thermoascus, Oxidation-Reduction |
| الوصف: | Lytic polysaccharide monooxygenases (LPMOs) are copper-containing enzymes capable of oxidizing crystalline cellulose and the enzyme has large practical application in the process of refining biomass. The LPMO catalytic mechanism still remains debated despite several proposed reaction mechanisms. Here, we report a long-lived intermediate (t½= 6 – 8 minutes) observed in an LPMO fromThermoascus aurantiacus(TaLPMO9A). The intermediate with a strong absorption around 420 nm is formed when reduced LPMO-Cu(I) reacts with H2O2. UV-vis absorption spectroscopy, electron paramagnetic resonance (EPR), and stopped-flow spectroscopy indicate that the observed long-lived intermediate involves the copper center and a nearby tyrosine (Tyr175). We propose that the reaction with H2O2first forms a highly reactive short-lived Cu(III)-intermediate which is subsequently transformed into the observed long-lived copper-dependent intermediate. Since sub-equimolar amount of H2O2to LPMO boosts oxidation of phosphoric acid swollen cellulose (PASC) suggests that the long-lived copper-dependent intermediate is part of the catalytic mechanism for LPMOs. The proposed mechanism offers new perspectives in the oxidative reaction mechanism of copper enzymes and hence for the biomass oxidation and the reactivity of copper in biological systems. |
| تدمد: | 1521-3765 0947-6539 |
| DOI: | 10.1002/chem.201903562 |
| URL الوصول: | https://explore.openaire.eu/search/publication?articleId=doi_dedup___::a58c59673f6fd4c45bf5af5c69cf9e8d https://doi.org/10.1002/chem.201903562 |
| Rights: | OPEN |
| رقم الانضمام: | edsair.doi.dedup.....a58c59673f6fd4c45bf5af5c69cf9e8d |
| قاعدة البيانات: | OpenAIRE |
| تدمد: | 15213765 09476539 |
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| DOI: | 10.1002/chem.201903562 |