Publication: Nuevas oxidorreductasas GMC de basidiomicetos ligninolíticos: screening genómico, mecanismo catalítico y potencial biotecnológico
Loading...
Files
Official URL
Full text at PDC
Publication Date
2018-09-19
Authors
Advisors (or tutors)
Editors
Journal Title
Journal ISSN
Volume Title
Publisher
Universidad Complutense de Madrid
Citations
Exportar
Abstract
La superfamilia de enzymas glucosa-metanol-colina (GMC) oxidasas/deshidrogenasas se compone de proteínas que contienen FAD filogenéticamente relacionadas entre sí que comparten un plegamiento común que se subdivide en dos dominios diferentes: el de unión a FAD y el de unión a sustrato. Algunas oxidorreductasas fúngicas que pertenecen a esta superfamilia desempeñan la función de enzimas auxiliares en el proceso de degradación de la lignocelulosa. La mayor parte de ellas son oxidorreductasas extracelulares que producen el H2O2 requerido: (i) por las peroxidasas de alto potencial redox para actuar sobre la lignina; o (ii) para desencadenar las reaciones de Fenton, que dan lugar a especies radicales de oxígeno que atacan a la lignocelulosa.El estudio de los genomas de 10 hongos seleccionados del orden Poliporales, los únicos organismos capaces de mineralizar totalmente la lignina, arrojó luz sobre la participación de 5 familias de oxidorreductasas GMC en la descomposición de la lignocelulosa. Estas fueron las glucosa oxidasas (GOX), celobiosa deshidrogenasas (CDH), piranosa 2-oxidasas (P2O), metanol oxidasas (MOX) y aril-alcohol oxidasas (AAO). Los estudios filogenéticos sugieren que estas enzimas comparten un ancestro común cuya diversificación tuvo lugar en una etapa más temprana de la evolución fúngica, que se caracterizó por el escaso número de estos genes GMC. Las AAO y las MOX resultaron ser las oxidorreductasas GMC más abundantes en los genomas seleccionados. El número de genes que codifican para estas proteínas varía ampliamente de un genoma a otro de acuerdo con las características ecofisiológicas de cada hongo...
The glucose-methanol-choline oxidase/dehydrogenase (GMC) superfamily of enzymes is composed of FAD-containing, phylogenetically-related proteins that share a common fold subdivided into two different domains: the FAD-binding and substrate-binding ones. Some fungal oxidoreductases belonging to the superfamily play a role as auxiliary enzymes in the lignocellulose-degrading process. Most of them are extracellular oxidoreductases that produce the H2O2 required: (i) by high redox potential peroxidases to act on lignin; or (ii) to trigger Fenton reactions, which give rise to radical oxygen species that attack lignocellulose.Investigation of the genomes of 10 selected Polyporales fungi, the only microorganisms able to completely mineralize lignin, shed light on the involvement of 5 families of GMC oxidoreductases in the lignocellulose decay. These were glucose oxidases (GOX), cellobiose dehydrogenases (CDH), pyranose 2-oxidases (P2O), methanol oxidases (MOX) and aryl-alcohol oxidases (AAO). Phylogenetic studies carried out suggest that they share a common ancestor whose diversification took place at a more ancestral stage of fungal evolution, which is characterized by a low number of these GMC genes. AAO and MOX proved to be the most abundant GMC oxidoreductases present in the selected genomes. The number of genes encoding for these enzymes varies from one genome to another according to the ecophysiology of the fungi. In fact, brown-rot fungi, which do not mineralize lignin but alter its structure to gain access to carbohydrates, lost most of their lignin-degrading enzymes and GMC repertoire, except MOX. These fungi cause the demethoxylation of lignin that releases methanol and relies on the reactivity of radical oxygen species stemming from H2O2. These findings point out the co-evolution of these fungal GMC enzymes with the lignin-degrading peroxidases...
The glucose-methanol-choline oxidase/dehydrogenase (GMC) superfamily of enzymes is composed of FAD-containing, phylogenetically-related proteins that share a common fold subdivided into two different domains: the FAD-binding and substrate-binding ones. Some fungal oxidoreductases belonging to the superfamily play a role as auxiliary enzymes in the lignocellulose-degrading process. Most of them are extracellular oxidoreductases that produce the H2O2 required: (i) by high redox potential peroxidases to act on lignin; or (ii) to trigger Fenton reactions, which give rise to radical oxygen species that attack lignocellulose.Investigation of the genomes of 10 selected Polyporales fungi, the only microorganisms able to completely mineralize lignin, shed light on the involvement of 5 families of GMC oxidoreductases in the lignocellulose decay. These were glucose oxidases (GOX), cellobiose dehydrogenases (CDH), pyranose 2-oxidases (P2O), methanol oxidases (MOX) and aryl-alcohol oxidases (AAO). Phylogenetic studies carried out suggest that they share a common ancestor whose diversification took place at a more ancestral stage of fungal evolution, which is characterized by a low number of these GMC genes. AAO and MOX proved to be the most abundant GMC oxidoreductases present in the selected genomes. The number of genes encoding for these enzymes varies from one genome to another according to the ecophysiology of the fungi. In fact, brown-rot fungi, which do not mineralize lignin but alter its structure to gain access to carbohydrates, lost most of their lignin-degrading enzymes and GMC repertoire, except MOX. These fungi cause the demethoxylation of lignin that releases methanol and relies on the reactivity of radical oxygen species stemming from H2O2. These findings point out the co-evolution of these fungal GMC enzymes with the lignin-degrading peroxidases...
Description
Tesis inédita de la Universidad Complutense de Madrid, Facultad de Ciencias Biológicas, Departamento de Bioquímica y Biología Molecular I, leída el 10-05-2017