title: N-glycan moieties of the crustacean egg yolk protein and their glycosylation sites.
abstract: Vitellogenin (Vg) is the precursor of the egg yolk glycoprotein of crustaceans. In the prawn Macrobrachium rosenbergii, Vg is synthesized in the hepatopancreas, secreted to the hemolymph, and taken up by means of receptor-mediated endocytosis into the oocytes. The importance of glycosylation of Vg lies in its putative role in the folding, processing and transport of this protein to the egg yolk and in the fact that the N-glycan moieties could provide a source of carbohydrate during embryogenesis. The present study describes, for the first time, the structure of the glycan moieties and their sites of attachment to the Vg of M. rosenbergii. Bioinformatics analysis revealed seven putative N-glycosylation sites in M. rosenbergii Vg; two of these glycosylation sites are conserved throughout the Vgs of decapod crustaceans from the Pleocyemata suborder (N 159 and N 660). The glycosylation of six putative sites of M. rosenbergii Vg (N 151, N 159, N ,168 N ,614 N 660 and N 2300) was confirmed; three of the confirmed glycosylation sites are localized around the N-terminally conserved N-glycosylation site N 159. From a theoretical three-dimensional structure, these three N-glycosylated sites N 151, N 159, and N 168 were localized on the surface of the Vg consensus sequence. In addition, an uncommon high mannose N-linked oligosaccharide structure with a glucose cap (Glc1Man9GlcNAc2) was characterized in the secreted Vg. These findings thus make a significant contribution to the structural elucidating of the crustacean Vg glycan moieties, which may shed light on their role in protein folding and transport and in recognition between Vg and its target organ, the oocyte.
authors.affiliation: Department of Biotechnology Engineering, Ben-Gurion University of the Negev, P.O.Box 653, Beer-Sheva, 84105, Israel.
authors.forename: Ziv
authors.initials: Z
authors.lastname: Roth
authors.forename: Shmuel
authors.initials: S
authors.lastname: Parnes
authors.forename: Simy
authors.initials: S
authors.lastname: Wiel
authors.forename: Amir
authors.initials: A
authors.lastname: Sagi
authors.forename: Nili
authors.initials: N
authors.lastname: Zmora
authors.forename: J Sook
authors.initials: JS
authors.lastname: Chung
authors.forename: Isam
authors.initials: I
authors.lastname: Khalaila
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D019295:Computational Biology; D003445:Crustacea / Q000737:chemistry*; D004527:Egg Proteins / Q000737:chemistry* / Q000378:metabolism; D006020:Glycopeptides / Q000737:chemistry / Q000378:metabolism; D006031:Glycosylation; D037102:Lectins / Q000378:metabolism; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism; D011134:Polysaccharides / Q000032:analysis* / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014819:Vitellogenins / Q000737:chemistry / Q000378:metabolism
chemical_list: D004527:Egg Proteins; D006020:Glycopeptides; D037102:Lectins; D009844:Oligosaccharides; D011134:Polysaccharides; D014819:Vitellogenins