Identification of a gene coding for a deglycosylating enzyme in Hypocrea jecorina.
An enzyme with mannosyl glycoprotein endo-N-acetyl-beta-D-glucosaminidase (ENGase)-type activity was partially purified from the extracellular medium of the mould Hypocrea jecorina (Trichoderma reesei). Internal peptides were generated and used to identify the gene in the T. reesei genome. The active enzyme is processed both at the N- and at the C-terminus. High-mannose-type glycoproteins are good substrates, whereas complex-type glycans are not hydrolysed. The enzyme represents the first fungal member of glycoside hydrolase family 18 with ENGase-type activity. Bacterial ENGases and the fungal chitinases belonging to the same family show very low homology with Endo T. Database searches identify several highly homologous genes in fungi and the activity is also found within other Trichoderma species. This ENGase activity, not coregulated with cellulase production, could be responsible for the extensive N-deglycosylation observed for several T. reesei cellulases.
Stals
Ingeborg
I
Department of Biochemistry and Microbiology, Faculty of Applied Engineering Sciences, Ghent University, Ghent, Belgium. ingeborg.stals@ugent.be
Samyn
Bart
B
Sergeant
Kjell
K
White
Theresa
T
Hoorelbeke
Katleen
K
Coorevits
An
A
Devreese
Bart
B
Claeyssens
Marc
M
Piens
Kathleen
K
D000595:Amino Acid Sequence; D002853:Chromatography, Liquid; D016000:Cluster Analysis; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D035901:Hypocrea / Q000201:enzymology* / Q000235:genetics*; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D010802:Phylogeny; D011499:Protein Processing, Post-Translational; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D005656:Fungal Proteins; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase