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534354 
Journal Article 
N-linked glycosylation of a beetle (Apriona germari) cellulase Ag-EGase II is necessary for enzymatic activity 
Wei, YD; Lee, KS; Gui, ZZ; Yoon, HJ; Kim, I; Je, YH; Lee, SM; Zhang, GZ; Guo, XJ; Sohn, HD; Jin, BR 
2006 
Yes 
Insect Biochemistry and Molecular Biology
ISSN: 0965-1748 
36 
6 
435-441 
English 
We previously reported that the beta-1,4-endoglucanase (EGase) belonging to glycoside hydrolase family (GHF) 45 of the Mulberry longicorn beetle, Apriona germari (Ag-EGase 11), has three potential N-linked glycosylation sites; these sites are located at amino acid residues 56-59 (NKSG), 99-102 (NSTF), and 237-239 (NYSstop). In the present Study. we analyze the functional role of these potential N-linked glycosylation sites. Tunicamycin treatment completely abolished the enzymatic activity of Ag-EGase II. To further elucidate the functional role of the N-linked glycosylation sites in Ag-EGase 11, we have assayed the cellulase enzyme activity in Ser58Gln. Thr101Gln, or Ser239Gln mutants. Lack of N-linked glycosylation site at residues 99-102 (NSTF), the site of which is conserved in known beetle GHF 45 cellulases, showed loss of enzyme activity and reduced the molecular mass of the enzyme, In contrast. mutations in Ser58Gln or Ser239Gln affected neither the activity nor the apparent molecular mass of the enzyme, indicating that these sites did not lead to N-linked glycosylation. The present study demonstrates that N-linked glycosylation at residues 99-102 (NSTF). while not essential for secretion, is required for Ag-EGase 11 enzyme activity. (c) 2006 Elsevier Ltd. All rights reserved. 
Apriona germari; baculovirus; beetle; cellulase; endoglucanase; enzyme; insect cells; mutation; N-linked glycosylation; mulberry longicorn beetle; polyacrylamide gels; cdna cloning; insect; cells; expression; system; secretion; termite; sites; gene