Topic
Xylanase
About: Xylanase is a research topic. Over the lifetime, 7099 publications have been published within this topic receiving 163793 citations.
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TL;DR: A new bifunctional xylanase (XynBE18) produced by Paenibacillus sp.
Abstract: Xylanases are utilized in a variety of industries for the breakdown of plant materials. Most native and engineered bifunctional/multifunctional xylanases have separate catalytic domains within the same polypeptide chain. Here we report a new bifunctional xylanase (XynBE18) produced by Paenibacillus sp. E18 with xylanase and β-1,3-1,4-glucanase activities derived from the same active center by substrate competition assays and site-directed mutagenesis of xylanase catalytic Glu residues (E129A and E236A). The gene consists of 981 bp, encodes 327 amino acids, and comprises only one catalytic domain that is highly homologous to the glycoside hydrolase family 10 xylanase catalytic domain. Recombinant XynBE18 purified from Escherichia coli BL21(DE3) showed specificity toward oat spelt xylan and birchwood xylan and β-1,3-1,4-glucan (barley β-glucan and lichenin). Homology modeling and molecular dynamic simulation were used to explore structure differences between XynBE18 and the monofunctional xylanase XynE2, which has enzymatic properties similar to those of XynBE18 but does not hydrolyze β-1,3-1,4-glucan. The cleft containing the active site of XynBE18 is larger than that of XynE2, suggesting that XynBE18 is able to bind larger substrates such as barley β-glucan and lichenin. Further molecular docking studies revealed that XynBE18 can accommodate xylan and β-1,3-1,4-glucan, but XynE2 is only accessible to xylan. These results indicate a previously unidentified structure-function relationship for substrate specificities among family 10 xylanases.
54 citations
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TL;DR: It is suggested that if the rice husk and the rice straw samples were pre-treated with xylanase prior to treatment with cellulase, the percentage increase of reducing sugar per 100g of substrate (starting material) was enhanced by about 29% and 41%, respectively.
54 citations
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TL;DR: This work identified a putative regulator of xylanase production with high similarity to the Aspergillus niger XlnR and the Trichoderma reesei Xyr1 proteins and found that the lack of this transcriptional activator had no effect on the induction of cellulases.
Abstract: Fusarium graminearum is a plant pathogen that causes severe economical losses by infecting numerous agriculturally important plants and until now most culture plants have only low levels of Fusarium resistance. The plant cell wall can be assumed as the first target that has to be overcome by plant pathogens. Therefore pathogenic organisms are known to produce a complex cocktail of plant cell wall lytic enzymes. Xylanases are besides cellulases the most prominent enzymes secreted by Fusarium during growth on plant cell walls. We identified a putative regulator of xylanase production with high similarity to the Aspergillus niger XlnR and the Trichoderma reesei Xyr1 proteins. Disruptant strains of F. graminearum were heavily impaired in xylose utilization and xylanase production on wheat cell walls. In contrast to other filamentous fungi the lack of this transcriptional activator had no effect on the induction of cellulases.
54 citations
01 Jan 2006
54 citations
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TL;DR: It was established that the crude fraction could release xylose from insoluble birchwood xylan, while the MEC was only able to produce xylobiose from this substrate, and the presence of both high xylanase and mannanase activity makes this MEC unusual.
54 citations