Xyloglucan breakdown by endo-xyloglucanase family 74 from Aspergillus fumigatus

Autor(es)

de Lima Damasio, Andre Ricardo ; Rubio, Marcelo Ventura ; Goncalves, Thiago Augusto ; Persinoti, Gabriela Felix ; Segato, Fernando ; Prade, Rolf Alexander ; Contesini, Fabiano Jares ; de Souza, Amanda Pereira ; Buckeridge, Marcos Silveira ; Squina, Fabio Marcio

• Tipo de documento: Artigo Científico
• Fonte: Applied Microbiology and Biotechnology; v. 101, n. 7, p. 2893-2903, APR 2017.
• Citações Web of Science: 7

Resumo

Xyloglucan is the most abundant hemicellulose in primary walls of spermatophytes except for grasses. Xyloglucan-degrading enzymes are important in lignocellulosic biomass hydrolysis because they remove xyloglucan, which is abundant in monocot-derived biomass. Fungal genomes encode numerous xyloglucanase genes, belonging to at least six glycoside hydrolase (GH) families. GH74 endo-xyloglucanases cleave xyloglucan backbones with unsubstituted glucose at the -1 subsite or prefer xylosyl-substituted residues in the -1 subsite. In this work, 137 GH74-related genes were detected by examining 293 Eurotiomycete genomes and Ascomycete fungi contained one or no GH74 xyloglucanase gene per genome. Another interesting feature is that the triad of tryptophan residues along the catalytic cleft was found to be widely conserved among Ascomycetes. The GH74 from Aspergillus fumigatus (AfXEG74) was chosen as an example to conduct comprehensive biochemical studies to determine the catalytic mechanism. AfXEG74 has no CBM and cleaves the xyloglucan backbone between the unsubstituted glucose and xylose-substituted glucose at specific positions, along the XX motif when linked to regions deprived of galactosyl branches. It resembles an endo-processive activity, which after initial random hydrolysis releases xyloglucan-oligosaccharides as major reaction products. This work provides insights on phylogenetic diversity and catalytic mechanism of GH74 xyloglucanases from Ascomycete fungi. (AU)

• Processo FAPESP: 14/18714-2 - Oxidação enzimática do bagaço de cana-de-açúcar: descoberta, caracterização e aplicação de novas enzimas oxidativas de carboidratos, voltadas para o desenvolvimento de um cell factory mais eficiente
• Beneficiário: Fernando Segato
• Linha de fomento: Auxílio à Pesquisa - Programa BIOEN - Apoio a Jovens Pesquisadores
• Processo FAPESP: 11/02169-7 - Aspergillus nidulans como modelo para expressão heteróloga de celulases e hemicelulases
• Beneficiário: André Ricardo de Lima Damasio
• Linha de fomento: Bolsas no Brasil - Pós-Doutorado
• 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
• Linha de fomento: Auxílio à Pesquisa - Programa BIOEN - Apoio a 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
• Linha de fomento: Auxílio à Pesquisa - Programa BIOEN - Apoio a Jovens Pesquisadores