Heterologous Expression and Characterization of an Acidic GH11 Family Xylanase from Hypocrea orientalis

Abstract

A gene encoding glycoside hydrolase family 11 xylanase (HoXyn11B) from Hypocrea orientalis EU7-22 was expressed in Pichia pastoris with a high activity (413 IU/ml). HoXyn11B was partly N-glycosylated and appeared two protein bands (19-29 kDa) on SDS-PAGE. The recombinant enzyme exhibited optimal activity at pH 4.5 and 55 °C, and retained more than 90% of the original activity after incubation at 50 °C for 60 min. The determined apparent K and V values using beechwood xylan were 10.43 mg/ml and 3246.75 IU/mg, respectively. The modes of action of recombinant HoXyn11B on xylo-oligosaccharides (XOSs) and beechwood xylan were investigated by thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS), which indicated that the modes of action of HoXyn11B are different from HoXyn11A since it is able to release a significant amount of xylose from various substrates. This study provides an opportunity to better understand the hydrolysis mechanisms of xylan by xylanases from Trichoderma.

Fungicidal Activity of Silver and Silica Nanoparticles against Aspergillus sydowii Isolated from the Soil in Western Saudi Arabia

“…Moreover, Aspergillus sydowii is a mesophilic soil saprobe that is a food contaminant as well as a human pathogen in immune-compromised patients [ 4 ]. Furthermore, the pathogenicity of Aspergillus sydowii depends on the genetic composition and immune status of the host [ 5 ]. Also, Aspergillus sydowii causes devastating aspergillosis in coral reefs but is a very rare cause of human disease [ 6 ].…”

Mining, Identification, and Characterization of Three Xylanases from the Microbiota of T. fuciformis with Its Companion Strains

“…Two active residues of Glu110 and Glu201 as general acid/base catalytic sites were located in this catalytic center region (Figure 2B). The observed information represented the typical characteristics of GH10 family xylanase for AsXyn1 and SsXyn and GH11 family xylanase for AsXyn2, suggesting that the three xylanase candidates had potential xylanase activity [18,19].…”

Aspergillus sydowii: Genome Analysis and Characterization of Two Heterologous Expressed, Non-redundant Xylanases

“…The enzyme xylanase II has a rather uncommon exception; it is able to degrade xylotriose with 9% activity but not xylotetraose. While other researchers found that, the shortest XOS converted by GH10 or GH 11 xylanases are the xylotriose or xylotetraose longer XOS ( Supplementary Table 10; Kolenová et al, 2006;Takahashi et al, 2013;Li et al, 2018;Han et al, 2019).…”

“…An activity of xylanase I and xylanase II with 181.1 and 121.5 U/mg was obtained in their N-terminal truncated versions, while only insoluble proteins were formed, if expressed with the corresponding fungal N-terminal secretion signal. Frequently, more complex eukaryotic expression systems, like Komagataella phaffii (formerly known as Pichia pastoris) or Yarrowia lipolytica, have to be used to express eukaryotic xylanases from A. niger, Trichioderma harzianum, Hypocrea orientalis, or Trichioderma reesei (He et al, 2009;Wang et al, 2014;Li et al, 2018) as they have the advantage of correct N-and O-glycosylation. The glycosylation can have different effects like enhancement of solubility (Solá and Griebenow, 2009), increased activity, as shown for the endo-cellulase IIa from Penicillium verrucosum (Dotsenko et al, 2016), or enhanced stability (Sarkar and Wintrode, 2011).…”