A novel acetyl xylan esterase enabling complete deacetylation of substituted xylans

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • Fakhria M. Razeq
  • Edita Jurak
  • Peter J. Stogios
  • Ruoyu Yan
  • Maija Tenkanen
  • Mirjam A. Kabel
  • Weijun Wang
  • Emma Master

Research units

  • University of Toronto
  • University of Helsinki
  • Wageningen University & Research

Abstract

Background: Acetylated 4-O-(methyl)glucuronoxylan (GX) is the main hemicellulose in deciduous hardwood, and comprises a β-(1→4)-linked xylopyranosyl (Xylp) backbone substituted by both acetyl groups and α-(1→2)-linked 4-O-methylglucopyranosyluronic acid (MeGlcpA). Whereas enzymes that target singly acetylated Xylp or doubly 2,3-O-acetyl-Xylp have been well characterized, those targeting (2-O-MeGlcpA)3-O-acetyl-Xylp structures in glucuronoxylan have remained elusive. Results: An unclassified carbohydrate esterase (FjoAcXE) was identified as a protein of unknown function from a polysaccharide utilization locus (PUL) otherwise comprising carbohydrate-active enzyme families known to target xylan. FjoAcXE was shown to efficiently release acetyl groups from internal (2-O-MeGlcpA)3-O-acetyl-Xylp structures, an activity that has been sought after but lacking in known carbohydrate esterases. FjoAcXE action boosted the activity of α-glucuronidases from families GH67 and GH115 by five and nine times, respectively. Moreover, FjoAcXE activity was not only restricted to GX, but also deacetylated (3-O-Araf)2-O-acetyl-Xylp of feruloylated xylooligomers, confirming the broad substrate range of this new carbohydrate esterase. Conclusion: This study reports the discovery and characterization of the novel carbohydrate esterase, FjoAcXE. In addition to cleaving singly acetylated Xylp, and doubly 2,3-O-acetyl-Xylp, FjoAcXE efficiently cleaves internal 3-O-acetyl-Xylp linkages in (2-O-MeGlcpA)3-O-acetyl-Xylp residues along with densely substituted and branched xylooligomers; activities that until now were missing from the arsenal of enzymes required for xylan conversion.

Details

Original languageEnglish
Article number74
Number of pages12
JournalBiotechnology for Biofuels
Volume11
Issue number1
Early online date22 Mar 2018
Publication statusPublished - Mar 2018
MoE publication typeA1 Journal article-refereed

    Research areas

  • Acetyl xylan esterase, Glucuronic acid, Polysaccharide utilization loci, SGNH hydrolase, Xylan, α-Glucuronidase

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