Mass spectral evidence for N-glycans with branching on fucose in a molluscan hemocyanin |
| |
Authors: | Gielens Constant Idakieva Krassimira Van den Bergh Viviane Siddiqui Nurul I Parvanova Katja Compernolle Frans |
| |
Institution: | Laboratory of Biochemistry, Chemistry Department, Katholieke Universiteit Leuven, Celestijnenlaan 200 G, 3001 Leuven-Heverlee, Belgium. constant.gielens@chem.kuleuven.ac.be |
| |
Abstract: | Glycopeptides, isolated from a trypsinolysate of functional unit (FU) RtH2-e of Rapana thomasiana hemocyanin subunit 2, were analysed by electrospray ionization mass spectrometry and MS/MS. From the molecular mass observed after deglycosylation, it was inferred that all glycopeptides shared the same peptide stretch 92-143 of FU RtH2-e with a glycosylation site at Asn-127. Besides the core structure Man(3)GlcNAc(2) for N-glycosylation, structures with a supplementary GlcNAc linked to either the Man(alpha1-3) or the Man(alpha1-6) arm and/or an additional tetrasaccharide unit connected to the other Man arm were observed, indicating the existence of microheterogeneity at the glycan level. The tetrasaccharide unit contains a central fucose moiety substituted with 3-O-methylgalactose and N-acetylgalactosamine, and linked to GlcNAc at the reducing end. This structure represents a novel N-glycan motif and is likely to be immunogenic. A second potential site for N-glycosylation in FU RtH2-e at Asn-17 was shown to be not glycosylated. |
| |
Keywords: | Deglycosylation Electrospray ionization mass spectrometry Fucose Gas chromatography Gastropod Hemocyanin Mollusc MS/MS N-Glycosylation Rapana thomasiana |
本文献已被 ScienceDirect PubMed 等数据库收录! |
|