Replacement of oxidizable residues predicted by QM-MM simulation of a fungal laccase generates variants with higher operational stability
| Autor: | Nina Pastor, Mayra Avelar, Marcela Ayala, Joaquin Ramirez-Ramirez |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Stereochemistry
Molecular Dynamics Simulation 010402 general chemistry 01 natural sciences Biochemistry Fungal Proteins Inorganic Chemistry QM/MM chemistry.chemical_compound Catalytic Domain Enzyme Stability Phenol Phenols Alanine Laccase biology 010405 organic chemistry Genetic Variation Active site biology.organism_classification 0104 chemical sciences chemistry biology.protein Isoleucine Oxidation-Reduction Coriolopsis gallica |
| Zdroj: | Journal of Inorganic Biochemistry. 178:125-133 |
| ISSN: | 0162-0134 |
| Popis: | In this work, we sought to obtain a more stable laccase with higher operational stability for the oxidation of phenols. During this reaction, phenoxy free radicals are produced that gradually inactivate the enzyme; the inactivation rate depends on the phenol chemical nature. In order to predict residues prone to oxidize within the active site, we simulated activated states of the catalytic region of a fungal laccase using QM-MM tools (Quantum Mechanics-Molecular Mechanics). After simulating the electron distribution in both the basal and activated state (plus or minus one electron) of several conformations of Coriolopsis gallica laccase, residues that could be susceptible to oxidation were identified, according to the values of spin density obtained from calculations. Three targets were selected (F357, F413, and F475) to be replaced by site-directed mutagenesis with less oxidizable residues such as leucine, alanine, and isoleucine. The resulting variants displayed a higher specific activity (from 1.5-to 4-fold) than the parental enzyme. Catalyst depletion during phenol oxidation was 2.5-fold lower for the variants, reflecting a higher operational stability. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|
Full Text from ScienceDirect