Abstract
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.