Expression of the Xylanase Gene from Pyromyces Finnis in Pichia Pastoris and Characterization of the Recombinant Protein

The heterologous expression and characteristics of a new xylanase from Pyromyces finnis have been described. The endo-l,4-β-xylanase XylP (EC 3.2.1.8) consists of 223 amino acids and 19 residues of a putative signal peptide in the N-terminal region. The amino acid sequence of the mature protein has the greatest homology with the sequence of the native catalytic N-terminal domain of Neocallimastix patriciarum endo-l,4-β-xylanase (84%). A synthetic nucleotide sequence encoding a mature XylP protein was expressed in Pichia pastoris. The purified recombinant enzyme showed activity with birch xylan and arabinoxylan. When using birch xylan as a substrate, the optimum pH for the enzyme was 5.0, and the optimum temperature was 50 °C. The specific activity of the xylanase was 4700 U/mg protein, and Km and Vmax were equal to 0.51 mg/mL and 7395.3 umol/(min∙mg), respectively. The recombinant XylP protein showed moderate thermal stability and high pH stability, resistance to digestive enzymes and protein inhibitors of grain xylanases. It was also shown that the Mg2+, Co2+ and Li+ ions have a positive effect on the enzyme activity. xylanase, xylan, feed enzyme, Pichia pastoris, Pyromyces finnis The work was performed with the financial support of the Ministry of Education and Science of Russia (Unique Project Identifier RFMEFI60717X0180) using the Unique Scientific Installation -National Bioresource Center «All-Russian Collection of Industrial Microorganisms», NRC «Kurchatov Institute» - GOSNIIGENETIKA