Characterization of the Biomass Degrading Enzyme GuxA from Acidothermus cellulolyticus

Neal Hengge, Sam Mallinson, Patthra Pason, Vladimir Lunin, Markus Alahuhta, Daehwan Chung, Michael Himmel, Janet Westpheling, Yannick Bomble

Research output: Contribution to journalArticlepeer-review

5 Scopus Citations


Microbial conversion of biomass relies on a complex combination of enzyme systems promoting synergy to overcome biomass recalcitrance. Some thermophilic bacteria have been shown to exhibit particularly high levels of cellulolytic activity, making them of particular interest for biomass conversion. These bacteria use varying combinations of CAZymes that vary in complexity from a single catalytic domain to large multi-modular and multi-functional architectures to deconstruct biomass. Since the discovery of CelA from Caldicellulosiruptor bescii which was identified as one of the most active cellulase so far identified, the search for efficient multi-modular and multi-functional CAZymes has intensified. One of these candidates, GuxA (previously Acel_0615), was recently shown to exhibit synergy with other CAZymes in C. bescii, leading to a dramatic increase in growth on biomass when expressed in this host. GuxA is a multi-modular and multi-functional enzyme from Acidothermus cellulolyticus whose catalytic domains include a xylanase/endoglucanase GH12 and an exoglucanase GH6, representing a unique combination of these two glycoside hydrolase families in a single CAZyme. These attributes make GuxA of particular interest as a potential candidate for thermophilic industrial enzyme preparations. Here, we present a more complete characterization of GuxA to understand the mechanism of its activity and substrate specificity. In addition, we demonstrate that GuxA exhibits high levels of synergism with E1, a companion endoglucanase from A. cellulolyticus. We also present a crystal structure of one of the GuxA domains and dissect the structural features that might contribute to its thermotolerance.

Original languageAmerican English
Article number6070
Number of pages13
JournalInternational Journal of Molecular Sciences
Issue number11
StatePublished - 2022

Bibliographical note

Publisher Copyright:
© 2022 by the authors. Licensee MDPI, Basel, Switzerland.

NREL Publication Number

  • NREL/JA-2700-82535


  • CAZymes
  • cellulose
  • enzyme synergy
  • lignocellulosic biomass
  • multifunctional enzymes
  • xylan


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