title: Glycan structures and antiviral effect of the structural subunit RvH2 of Rapana hemocyanin.
abstract: Molluscan hemocyanins are very large biological macromolecules and they act as oxygen-transporting glycoproteins. Most of them are glycoproteins with molecular mass around 9000 kDa. The oligosaccharide structures of the structural subunit RvH2 of Rapana venosa hemocyanin (RvH) were studied by sequence analysis of glycans using MALDI-TOF-MS and tandem mass spectrometry on a Q-Trap mass spectrometer after enzymatical liberation of the N-glycans from the polypeptides. Our study revealed a highly heterogeneous mixture of glycans of the compositions Hex(0-9) HexNAc(2-4) Hex(0-3) Pent(0-3) Fuc(0-3). A novel type of N-glycan, with an internal fucose residue connecting one GalNAc(β1-2) and one hexuronic acid, was detected, as also occurs in subunit RvH1. A glycan with the same structure but with two deoxyhexose residues was observed as a doubly charged ion. Antiviral effects of the native molecules of RvH and also of Helix lucorum hemocyanin (HlH), of their structural subunits, and of the glycosylated functional unit RvH2-e and the non-glycosylated unit RvH2-c on HSV virus type 1 were investigated. Only glycosylated FU RvH2-e exhibits this antiviral activity. The carbohydrate chains of the FU are likely to interact with specific regions of glycoproteins of HSV, through van der Waals interactions in general or with certain amino acid residues in particular. Several clusters of these residues can be identified on the surface of RvH2-e.
authors.affiliation: Institute of Organic Chemistry, Bulgarian Academy of Sciences, G. Bonchev 9, Sofia 1113, Bulgaria. pda54@abv.bg
authors.forename: Pavlina
authors.initials: P
authors.lastname: Dolashka
authors.forename: Ludmyla
authors.initials: L
authors.lastname: Velkova
authors.forename: Stoyan
authors.initials: S
authors.lastname: Shishkov
authors.forename: Kalina
authors.initials: K
authors.lastname: Kostova
authors.forename: Aleksander
authors.initials: A
authors.lastname: Dolashki
authors.forename: Ivan
authors.initials: I
authors.lastname: Dimitrov
authors.forename: Boris
authors.initials: B
authors.lastname: Atanasov
authors.forename: Bart
authors.initials: B
authors.lastname: Devreese
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Voelter
authors.forename: Jozef
authors.initials: J
authors.lastname: Van Beeumen
mesh_terms: D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology*; D002236:Carbohydrate Conformation; D006433:Hemocyanins / Q000737:chemistry*; D018259:Herpesvirus 1, Human / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D011134:Polysaccharides / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D000998:Antiviral Agents; D011134:Polysaccharides; D006433:Hemocyanins