Covalent binding of three epoxyalkyl xylosides to the active site of endo-1,4-xylanase II from Trichoderma reesei

Biochemistry. 1996 Jul 23;35(29):9617-24. doi: 10.1021/bi953052n.

Abstract

The three-dimensional structures of endo-1,4-xylanase II (XYNII) from Trichoderma reesei complexed with 4,5-epoxypentyl beta-D-xyloside (X-O-C5),3,4-epoxybutyl beta-D-xyloside (X-O-C4), and 2,3-epoxypropyl beta-D-xyloside (X-O-C3) were determined by X-ray crystallography. High-resolution measurement revealed clear electron densities for each ligand. Both X-O-C5 and X-O-C3 were found to form a covalent bond with the putative nucleophile Glu86. Unexpectedly, X-O-C4 was found to bind to the putative acid/base catalyst Glu177. In all three complexes, clear conformational changes were found in XYNII compared to the native structure. These changes were largest in the X-O-C3 complex structure.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzoates / metabolism
  • Benzoic Acid
  • Binding Sites
  • Carbohydrate Conformation
  • Carbohydrate Sequence
  • Crystallography, X-Ray
  • Endo-1,4-beta Xylanases
  • Enzyme Inhibitors / chemistry
  • Enzyme Inhibitors / metabolism*
  • Epoxy Compounds / metabolism*
  • Glycosides / chemistry
  • Glycosides / metabolism*
  • Hydrogen Bonding
  • Hydrogen-Ion Concentration
  • Models, Molecular
  • Molecular Sequence Data
  • Molecular Structure
  • Oligosaccharides / chemistry
  • Oligosaccharides / metabolism
  • Protein Conformation
  • Trichoderma / enzymology*
  • Xylosidases / antagonists & inhibitors
  • Xylosidases / chemistry*
  • Xylosidases / metabolism

Substances

  • Benzoates
  • Enzyme Inhibitors
  • Epoxy Compounds
  • Glycosides
  • Oligosaccharides
  • xylosides
  • Benzoic Acid
  • Xylosidases
  • Endo-1,4-beta Xylanases