Covalent binding of three epoxyalkyl xylosides to the active site of endo-1,4-xylanase II from Trichoderma reesei.
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.
Havukainen
R
R
Department of Chemistry, University of Joensuu, Finland.
Törrönen
A
A
Laitinen
T
T
Rouvinen
J
J
D001565:Benzoates / Q000378:metabolism; D019817:Benzoic Acid; D001665:Binding Sites; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D018360:Crystallography, X-Ray; D043364:Endo-1,4-beta Xylanases; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism*; D006027:Glycosides / Q000737:chemistry / Q000378:metabolism*; D006860:Hydrogen Bonding; D006863:Hydrogen-Ion Concentration; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D011487:Protein Conformation; D014242:Trichoderma / Q000201:enzymology*; D014995:Xylosidases / Q000037:antagonists & inhibitors / Q000737:chemistry* / Q000378:metabolism
D001565:Benzoates; D004791:Enzyme Inhibitors; D004852:Epoxy Compounds; D006027:Glycosides; D009844:Oligosaccharides; C010807:xylosides; D019817:Benzoic Acid; D014995:Xylosidases; D043364:Endo-1,4-beta Xylanases