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Activities of Secreted Aryl Alcohol Quinone Oxidoreductases from Pycnoporus cinnabarinus Provide Insights into Fungal Degradation of Plant Biomass.
- Source :
-
Applied and environmental microbiology [Appl Environ Microbiol] 2016 Apr 04; Vol. 82 (8), pp. 2411-2423. Date of Electronic Publication: 2016 Apr 04 (Print Publication: 2016). - Publication Year :
- 2016
-
Abstract
- Auxiliary activities family 3 subfamily 2 (AA3&#95;2) from the CAZy database comprises various functions related to ligninolytic enzymes, such as fungal aryl alcohol oxidases (AAO) and glucose oxidases, both of which are flavoenzymes. The recent study of the Pycnoporus cinnabarinus CIRM BRFM 137 genome combined with its secretome revealed that four AA3&#95;2 enzymes are secreted during biomass degradation. One of these AA3&#95;2 enzymes, scf184803.g17, has recently been produced heterologously in Aspergillus niger Based on the enzyme's activity and specificity, it was assigned to the glucose dehydrogenases (PcinnabarinusGDH [PcGDH]). Here, we analyze the distribution of the other three AA3&#95;2 enzymes (scf185002.g8, scf184611.g7, and scf184746.g13) to assess their putative functions. These proteins showed the highest homology with aryl alcohol oxidase from Pleurotus eryngii Biochemical characterization demonstrated that they were also flavoenzymes harboring flavin adenine dinucleotide (FAD) as a cofactor and able to oxidize a wide variety of phenolic and nonphenolic aryl alcohols and one aliphatic polyunsaturated primary alcohol. Though presenting homology with fungal AAOs, these enzymes exhibited greater efficiency in reducing electron acceptors (quinones and one artificial acceptor) than molecular oxygen and so were defined as aryl-alcohol:quinone oxidoreductases (AAQOs) with two enzymes possessing residual oxidase activity (PcAAQO2 and PcAAQO3). Structural comparison of PcAAQO homology models with P. eryngii AAO demonstrated a wider substrate access channel connecting the active-site cavity to the solvent, explaining the absence of activity with molecular oxygen. Finally, the ability of PcAAQOs to reduce radical intermediates generated by laccase from P. cinnabarinus was demonstrated, shedding light on the ligninolytic system of this fungus.<br /> (Copyright © 2016, American Society for Microbiology. All Rights Reserved.)
- Subjects :
- Alcohol Oxidoreductases chemistry
Alcohol Oxidoreductases genetics
Biomass
Biotransformation
Coenzymes metabolism
Flavin-Adenine Dinucleotide metabolism
Flavoproteins chemistry
Flavoproteins genetics
Flavoproteins metabolism
Models, Molecular
Protein Conformation
Sequence Homology, Amino Acid
Substrate Specificity
Alcohol Oxidoreductases metabolism
Lignin metabolism
Pycnoporus enzymology
Quinones metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1098-5336
- Volume :
- 82
- Issue :
- 8
- Database :
- MEDLINE
- Journal :
- Applied and environmental microbiology
- Publication Type :
- Academic Journal
- Accession number :
- 26873317
- Full Text :
- https://doi.org/10.1128/AEM.03761-15