Please use this identifier to cite or link to this item:
Type: Artigo
Title: Redesigning N-glycosylation sites in a GH3 β-xylosidase improves the enzymatic efficiency
Author: Rubio, Marcelo Ventura
Terrasan, César Rafael Fanchini
Contesini, Fabiano Jares
Zubieta, Mariane Paludetti
Gerhardt, Jaqueline Aline
Oliveira, Leandro Cristante
Gonçalves, Any Elisa de Souza Schmidt
Almeida, Fausto
Smith, Bradley Joseph
Souza, Gustavo Henrique Martins Ferreira de
Dias, Artur Hermano Sampaio
Skaf, Munir
Damasio, André
Abstract: β-Xylosidases are glycoside hydrolases (GHs) that cleave xylooligosaccharides and/or xylobiose into shorter oligosaccharides and xylose. Aspergillus nidulans is an established genetic model and good source of carbohydrate-active enzymes (CAZymes). Most fungal enzymes are N-glycosylated, which influences their secretion, stability, activity, signalization, and protease protection. A greater understanding of the N-glycosylation process would contribute to better address the current bottlenecks in obtaining high secretion yields of fungal proteins for industrial applications. In this study, BxlB—a highly secreted GH3 β-xylosidase from A. nidulans, presenting high activity and several N-glycosylation sites—was selected for N-glycosylation engineering. Several glycomutants were designed to investigate the influence of N-glycans on BxlB secretion and function. The non-glycosylated mutant (BxlBnon-glyc) showed similar levels of enzyme secretion and activity compared to the wild-type (BxlBwt), while a partially glycosylated mutant (BxlBN1;5;7) exhibited increased activity. Additionally, there was no enzyme secretion in the mutant in which the N-glycosylation context was changed by the introduction of four new N-glycosylation sites (BxlBCC), despite the high transcript levels. BxlBwt, BxlBnon-glyc, and BxlBN1;5;7 formed similar secondary structures, though the mutants had lower melting temperatures compared to the wild type. Six additional glycomutants were designed based on BxlBN1;5;7, to better understand its increased activity. Among them, the two glycomutants which maintained only two N-glycosylation sites each (BxlBN1;5 and BxlBN5;7) showed improved catalytic efficiency, whereas the other four mutants’ catalytic efficiencies were reduced. The N-glycosylation site N5 is important for improved BxlB catalytic efficiency, but needs to be complemented by N1 and/or N7. Molecular dynamics simulations of BxlBnon-glyc and BxlBN1;5 reveals that the mobility pattern of structural elements in the vicinity of the catalytic pocket changes upon N1 and N5 N-glycosylation sites, enhancing substrate binding properties which may underlie the observed differences in catalytic efficiency between BxlBnon-glyc and BxlBN1;5. This study demonstrates the influence of N-glycosylation on A. nidulans BxlB production and function, reinforcing that protein glycoengineering is a promising tool for enhancing thermal stability, secretion, and enzymatic activity. Our report may also support biotechnological applications for N-glycosylation modification of other CAZymes
Subject: Aspergillus nidulans
Country: Reino Unido
Editor: Springer Nature
Rights: Fechado
Identifier DOI: 10.1186/s13068-019-1609-2
Date Issue: Dec-2019
Appears in Collections:IB - Artigos e Outros Documentos

Files in This Item:
File Description SizeFormat 
000497451600002.pdf1.86 MBAdobe PDFView/Open

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.