Involvement of glycan chains in the antigenicity of Rapana thomasiana hemocyanin.
Functional unit (FU) RtH2-e from Rapana thomasiana hemocyanin (Hc) was degraded into small fragments with chymotrypsin. The glycopeptides were separated from the non-glycosylated peptides by chromatography on Concanavalin-A-Sepharose and characterized by mass spectrometry. The glycan part of the glycopeptides (all with common peptide stretch of 14 amino acids) consists of the classical trimannosyl-N,N-diacetylchitobiose core for N-glycosylation, predominantly extended with a unique tetrasaccharide that is branched on fucose. In inhibition ELISA experiments, the glycopeptides interfered in the complex formation between FU RtH2-e and rabbit antibodies against Rapana Hc (about 30% of inhibition). The inhibition also was retained after treatment of the glycopeptides with pronase in order to completely destroy the peptide part. The inhibitory effect of the non-glycosylated peptides, on the other hand, was very low. This study thus demonstrates that the glycans attached to FU RtH2-e contribute to the antigenicity of Rapana Hc.
Division of Biochemistry, Molecular and Structural Biology, Chemistry Department, Katholieke Universiteit Leuven, Celestijnenlaan 200 G, 3001 Leuven-Heverlee, Belgium.
Nurul Islam
NI
Siddiqui
Krassimira
K
Idakieva
Bert
B
Demarsin
Lyubka
L
Doumanova
Frans
F
Compernolle
Constant
C
Gielens
D000595:Amino Acid Sequence; D000818:Animals; D049851:Gastropoda / Q000737:chemistry / Q000276:immunology* / Q000378:metabolism; D006020:Glycopeptides / Q000737:chemistry / Q000276:immunology; D006433:Hemocyanins / Q000737:chemistry* / Q000276:immunology*; D013058:Mass Spectrometry; D008954:Models, Biological; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000737:chemistry / Q000276:immunology*
D006020:Glycopeptides; D011134:Polysaccharides; D006433:Hemocyanins