Author(s):
Costa, Júlia 
; Ashford, David A. ; Nimtz, Manfred ; Bento, Isabel ; Frazão, Carlos ; Esteves, Cristina L. ; Faro, Carlos J. ; Kervinen, Jukka ; Pires, Euclides ; VerÍssimo, Paula ; Wlodawer, Alexander ; Carrondo, Maria Arménia
Date: 1997
Persistent ID: http://hdl.handle.net/10316/8137
Origin: Estudo Geral - Universidade de Coimbra
Description
Plant aspartic proteinases characterised at the molecular level contain one or more consensus N-glycosylation sites [Runeberg-Roos, P., Törmäkangas, K. & Östman, A. (1991) Eur. J. Biochem. 202, 102120131027; Asakura, T., Watanabe, H., Abe, K. & Arai, S. (1995) Eur. J. Biochem. 232, 77201383; Veríssimo, P., Faro, C., Moir, A. J. G., Lin, Y., Tang, J. & Pires, E. (1996) Eur. J. Biochem. 235, 76220137681. We found that the glycosylation sites are occupied for the barley (Hordeum vulgare L.) aspartic proteinase (Asn333) and the cardoon (Cynara cardunculus L.) aspartic proteinase, cardosin A (Asn70 and Asn363). The oligosaccharides from each site were released from peptide pools by enzymatic hydrolysis with peptide-N-glycanase A or by hydrazinolysis and their structures were determined by exoglycosidase sequencing combined with matrix-assisted laser desorption/ionization time of flight mass spectrometry. It was observed that 6% of the oligosaccharides from the first glycosylation site of cardosin A are of the oligomannose type. Modified type glycans with proximal Fuc and without Xyl account for about 82%, 14% and 3% of the total oligosaccharides from the first and the second glycosylation sites of cardosin A and from H. vulgare aspartic proteinase, respectively. Oligosaccharides with Xyl but without proximal Fuc were only detected in the latter proteinase (4%). Glycans with proximal Fuc and Xyl account for 6%, 86% and 92% of the total oligosaccharides from the first and second glycosylation sites of cardosin A and from H. vulgure aspartic proteinase, respectively. http://dx.doi.org/10.1111/j.1432-1033.1997.t01-1-00695.x
