Thermostability and xylan-hydrolyzing property of endoxylanase expressed in yeast Saccharomyces cerevisiae

Abstract

The endoxylanase gene (ñóå_, GeneBank access code U51675), including its signal sequence, from _~Åáääìë spp. was amplified and connected in frame downstream of yeast ^aeN promoter and then the resulting plasmid, pAEDX-1, was introduced into p~ÅÅÜ~êçãóÅÉë=ÅÉêÉîáëá~É. When the yeast transformants were grown on YPD medium, the majority of endoxylanase activity was detected in the extracellular culture medium, indicating that the signal peptide of _~Åáääìë endoxylanase functioned well in yeast. In the batch cultivation of yeast transformants, the total expression level of endoxylanase and secretion efficiency were measured to be about 9.8 U/mL and 66.2%, respectively. The extracellular endoxylanase expressed in yeast showed an enhanced thermal stability due to the k-linked glycosylation. Through the hydrolysis of birchwood xylan with the endoxylanase, it was found that xylobiose and xylotriose were produced as major products with equimolar ratio. © KSBB hÉóïçêÇëW=båÇçñóä~å~ëÉ, Saccharomyces cerevisiaeI íÜÉêãçëí~Äáäáíó, ñóäçÄáçëÉI=ñóäçíêáçëÉ=

Enhanced thermostability of a mesophilic xylanase byN-terminal replacement designed by molecular dynamics simulation

“…Many researchers also reported the effect of a disulfide bridge on the thermostability of xylanases . Besides, N ‐ and/or O ‐glycosylation were structural factors in resisting the thermal inactivation of enzymes as reported previously . To demonstrate whether the N ‐glycosylation of NhXyn11 57 contributed to its elevated thermostability, the N ‐deglycosylation of NhXyn11 57 was performed by site‐directed mutagenesis of N ‐glycosylation sites (N42Q and N62A).…”

“…29,30 Besides, N-and/or O-glycosylation were structural factors in resisting the thermal inactivation of enzymes as reported previously. 31,32 To demonstrate whether the N-glycosylation of NhXyn11 57 contributed to its elevated thermostability, the N-deglycosylation of NhXyn11 57 was performed by site-directed mutagenesis of Nglycosylation sites (N42Q and N62A). Our test results displayed that there were no obvious differences between the N-glycosylated and N-deglycosylated NhXyn11 57 in physicochemical and enzymatic properties, except for their apparent molecular masses (date not shown).…”

Engineering hyperthermostability into a mesophilic family 11 xylanase from Aspergillus oryzae by in silico design of N‐terminus substitution

“…In addition, two residue substitutions with Pro at positions 9 and 26, respectively, may contribute to the elevated thermostability of AEx11A by fitting well into the loop geometry. Besides, a major structural factor of resisting the thermal inactivation of proteins reported previously may be the N‐glycosylation (Lee et al, 2009). An only putative N‐glycosylation site (N42‐W43‐S44) in AEx11A was introduced by N‐terminus substitution.…”

Saccharomyces cerevisiae strains for second-generation ethanol production: from academic exploration to industrial implementation

“… 2004 ; Lee et al. 2009 ). The ability to ferment cellobiose has been successfully introduced into S. cerevisiae by combined expression of a heterologous cellobiose transporter and β-glucosidase (Galazka et al.…”