Structural characterization of N-linked oligosaccharides from cellobiohydrolase I secreted by the filamentous fungus Trichoderma reesei RUTC 30.
We have characterized the primary structures of the predominant N-linked oligosaccharides on cellobiohydrolase I from the filamentous fungus Trichoderma reesei RUTC30. Different enzymatic and chromatographic techniques were used to analyze six oligosaccharides. The combined data showed that the fungal carbohydrates have a core structure that is identical to the mammalian N-linked core. In the bulk of the N-glycans, the alpha-1,3 arm is extended with two mannoses and a glucose, suggesting incomplete processing of the oligosaccharides in the endoplasmic reticulum. The alpha-1,6 arm shows a remarkable heterogeneity: in addition to alpha-1,2-Man and alpha-1,6-Man, the presence of a terminal mannose alpha-1,6-phosphodiester was observed. This latter substituent has not been characterized before on mannosidase-processed N-glycan and its function and synthesis pathway are entirely unknown. The predominant N-glycans on cellobiohydrolase I can be represented as follows: GlcMan8GlcNAc2, GlcMan7GlcNAc2, Man7GlcNAc2, ManPGlcMan7GlcNAc2, GlcMan5GlcNAc2 and Man5GlcNAc2.
Maras
M
M
Laboratory of Molecular Biology, Flanders Interuniversity Institute for Biotechnology and University of Ghent, Belgium.
De Bruyn
A
A
Schraml
J
J
Herdewijn
P
P
Claeyssens
M
M
Fiers
W
W
Contreras
R
R
D002240:Carbohydrate Sequence; D002480:Cellulase / Q000737:chemistry*; D043366:Cellulose 1,4-beta-Cellobiosidase; D005656:Fungal Proteins / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis*; D014242:Trichoderma / Q000737:chemistry* / Q000201:enzymology
D005656:Fungal Proteins; D009844:Oligosaccharides; D002480:Cellulase; D043366:Cellulose 1,4-beta-Cellobiosidase