The structural basis of fungal glucuronoyl esterase activity on natural substrates

Nat Commun. 2020 Feb 24;11(1):1026. doi: 10.1038/s41467-020-14833-9.


Structural and functional studies were conducted of the glucuronoyl esterase (GE) from Cerrena unicolor (CuGE), an enzyme catalyzing cleavage of lignin-carbohydrate ester bonds. CuGE is an α/β-hydrolase belonging to carbohydrate esterase family 15 (CE15). The enzyme is modular, comprised of a catalytic and a carbohydrate-binding domain. SAXS data show CuGE as an elongated rigid molecule where the two domains are connected by a rigid linker. Detailed structural information of the catalytic domain in its apo- and inactivated form and complexes with aldouronic acids reveal well-defined binding of the 4-O-methyl-a-D-glucuronoyl moiety, not influenced by the nature of the attached xylo-oligosaccharide. Structural and sequence comparisons within CE15 enzymes reveal two distinct structural subgroups. CuGE belongs to the group of fungal CE15-B enzymes with an open and flat substrate-binding site. The interactions between CuGE and its natural substrates are explained and rationalized by the structural results, microscale thermophoresis and isothermal calorimetry.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carbohydrates
  • Catalytic Domain*
  • Cell Wall / metabolism
  • Crystallography, X-Ray
  • Esterases / isolation & purification
  • Esterases / metabolism*
  • Esterases / ultrastructure
  • Fungal Proteins / isolation & purification
  • Fungal Proteins / metabolism*
  • Fungal Proteins / ultrastructure
  • Glucuronic Acid / metabolism*
  • Hydrolysis
  • Lignin / metabolism
  • Polyporales / enzymology*
  • Protein Structure, Secondary
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Recombinant Proteins / ultrastructure
  • Scattering, Small Angle
  • Structure-Activity Relationship
  • Substrate Specificity
  • X-Ray Diffraction


  • Carbohydrates
  • Fungal Proteins
  • Recombinant Proteins
  • lignocellulose
  • Glucuronic Acid
  • Lignin
  • Esterases