Thermostability improvement of a Talaromyces leycettanus xylanase by rational protein engineering

Abstract

Thermophilic xylanases with high catalytic efficiency are of great interest in the biofuel, food and feed industries. This study identified a GH11 xylanase gene, Tlxyn11B, in Talaromyces leycettanus JCM12802. Recombinant TlXyn11B produced in Pichia pastoris is distinguished by high specific activity (8259 ± 32 U/mg with beechwood xylan as substrate) and excellent pH stability (from 1.0 to 10.5). The beechwood xylan hydrolysates consisted mainly of xylobiose, xylotriose and xylotetraose, thus TlXyn11B could be used for the production of prebiotic xylooligosaccharide. By using the structure-based rational approach, the N-terminal sequence of TlXyn11B was modified for thermostability improvement. Mutants S3F and S3F/D35V/I/Q/M had elevated T m values of 60.01 to 67.84 °C, with S3F/D35I the greatest. Homology modeling and molecular dynamics (MD) simulation analysis revealed that the substituted F3 and I35 formed a sandwich structure with S45 and T47, which may enhance the overall structure rigidity with lowered RMSD values. This study verifies the efficiency of rational approach in thermostability improvement and provides a xylanase candidate of GH11 with great commercialization potential.

A novel thermostable aspartic protease from Talaromyces leycettanus and its specific autocatalytic activation through an intermediate transition state

“…xylanase (34), β-glucanase (35), and α-Amylase (36). In this study, a novel aspartic protease precursor comprising of 424 amino acid residues was identified in Talaromyces leycettanus and was determined to be a member of the A1 family of aspartic proteases.…”

A detailed overview of xylanases: an emerging biomolecule for current and future prospective

“…Thielavia terrestris, (Garcia-Huante et al 2017), Talaromyces thermophilus (Maalej et al 2009), Paecilomyces thermophile (Fan et al 2012), Achaetomium sp. X2-8 (Chadha et al 2019), Rhizomucor pusillus (Hüttner et al 2018), Rasamsonia emersonii, (Martínez et al 2016) T. Leycettanus (Wang et al 2017), Melanocarpus albomyces (Gupta et al 2013) and Aspergillus oryzae LC1 (Bhardwaj et al 2019) were found to be producer of hyper-thermophilic active xylanase. Several alkali stable xylanases were obtained from different fungal strains such as Paenibacillus barcinonensis (Valenzuela et al 2010), Aspergillus fumigatus MA28 (Bajaj and Abbass 2011), Cladosporium oxysporum (Guan et al 2016) and Aspergillus oryzae LC1 (Bhardwaj et al 2019).…”

A novel thermostable aspartic protease fromTalaromyces leycettanusand its specific autocatalytic activation through an intermediate transition state

“…Extremophiles are excellent sources of novel enzymes that can retain their integrity and function under extreme reaction conditions (32). Talaromyces leycettanus JCM12802, a thermotolerant fungus, that has an optimal growth temperature of 42 °C, is the source of various thermostable hydrolases including β -mannanase (33), xylanase (34), β -glucanase (35), and α -Amylase (36). In this study, a novel aspartic protease precursor comprising of 424 amino acid residues was identified in Talaromyces leycettanus and was determined to be a member of the A1 family of aspartic proteases.…”