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

Hailong Li, Hongli Wu, Fengjiao Jiang, Jinlian Wu, Yong Xue, Lihui Gan, Jian Liu, Minnan Long

Applied biochemistry and biotechnology 2018 Jan

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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 m and V max 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.

Citation

Hailong Li, Hongli Wu, Fengjiao Jiang, Jinlian Wu, Yong Xue, Lihui Gan, Jian Liu, Minnan Long. Heterologous Expression and Characterization of an Acidic GH11 Family Xylanase from Hypocrea orientalis. Applied biochemistry and biotechnology. 2018 Jan;184(1):228-238