| Texto completo | |
| Autor(es): |
Segato, Fernando
[1]
;
Damasio, Andre R. L.
[1, 2]
;
de Lucas, Rosymar C.
[1]
;
Squina, Fabio M.
[2]
;
Prade, Rolf A.
[1, 2]
Número total de Autores: 5
|
| Afiliação do(s) autor(es): | [1] Oklahoma State Univ, Dept Microbiol & Mol Genet, Stillwater, OK 74078 - USA
[2] Ctr Nacl Pesquisa Energia Mat, Lab Nacl Ciencia & Tecnol Bioetanol, Campinas, SP - Brazil
Número total de Afiliações: 2
|
| Tipo de documento: | Artigo de Revisão |
| Fonte: | MICROBIOLOGY AND MOLECULAR BIOLOGY REVIEWS; v. 78, n. 4, p. 588-613, DEC 2014. |
| Citações Web of Science: | 33 |
| Resumo | |
Biomass is constructed of dense recalcitrant polymeric materials: proteins, lignin, and holocellulose, a fraction constituting fibrous cellulose wrapped in hemicellulose-pectin. Bacteria and fungi are abundant in soil and forest floors, actively recycling biomass mainly by extracting sugars from holocellulose degradation. Here we review the genome-wide contents of seven Aspergillus species and unravel hundreds of gene models encoding holocellulose-degrading enzymes. Numerous apparent gene duplications followed functional evolution, grouping similar genes into smaller coherent functional families according to specialized structural features, domain organization, biochemical activity, and genus genome distribution. Aspergilli contain about 37 cellulase gene models, clustered in two mechanistic categories: 27 hydrolyze and 10 oxidize glycosidic bonds. Within the oxidative enzymes, we found two cellobiose dehydrogenases that produce oxygen radicals utilized by eight lytic polysaccharide monooxygenases that oxidize glycosidic linkages, breaking crystalline cellulose chains and making them accessible to hydrolytic enzymes. Among the hydrolases, six cellobiohydrolases with a tunnel-like structural fold embrace single crystalline cellulose chains and cooperate at nonreducing or reducing end termini, splitting off cellobiose. Five endoglucanases group into four structural families and interact randomly and internally with cellulose through an open cleft catalytic domain, and finally, seven extracellular beta-glucosidases cleave cellobiose and related oligomers into glucose. Aspergilli contain, on average, 30 hemicellulase and 7 accessory gene models, distributed among 9 distinct functional categories: the backbone-attacking enzymes xylanase, mannosidase, arabinase, and xyloglucanase, the short-side-chain-removing enzymes xylan alpha-1,2-glucuronidase, arabinofuranosidase, and xylosidase, and the accessory enzymes acetyl xylan and feruloyl esterases. (AU) | |
| Processo FAPESP: | 13/18910-3 - Secreção de glicoproteínas heterólogas em Aspergillus: efeito do padrão de glicosilação em parâmetros funcionais de glicosil hidrolases |
| Beneficiário: | André Ricardo de Lima Damasio |
| Modalidade de apoio: | Bolsas no Brasil - Programa BIOEN - Jovens Pesquisadores |
| Processo FAPESP: | 12/20549-4 - Secreção de glicoproteínas heterólogas em Aspergillus: efeito do padrão de glicosilação em parâmetros funcionais de glicosil hidrolases |
| Beneficiário: | André Ricardo de Lima Damasio |
| Modalidade de apoio: | Auxílio à Pesquisa - Programa BIOEN - Jovens Pesquisadores |
| Processo FAPESP: | 08/58037-9 - Geração de biblioteca para conversão enzimática de biomassa a partir de metagenoma do solo |
| Beneficiário: | Fábio Márcio Squina |
| Modalidade de apoio: | Auxílio à Pesquisa - Programa BIOEN - Jovens Pesquisadores |
| Processo FAPESP: | 10/18198-3 - Biologia de sistemas das interações microbianas na decomposição do bagaço de cana |
| Beneficiário: | Fábio Márcio Squina |
| Modalidade de apoio: | Auxílio à Pesquisa - Pesquisador Visitante - Internacional |