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Apopolysialoglycoprotein (PSGP) This family represents a series of 13 reside repeats found in the apopolysialoglycoprotein of Oncorhynchus mykiss (Rainbow trout) and Oncorhynchus masou (Cherry salmon). Polysialoglycoprotein (PSGP) of unfertilized eggs of rainbow trout consists of tandem repeats of a glycotridecapeptide, Asp-Asp-Ala-Thr*-Ser*-Glu-Ala-Ala-Thr*-Gly-Pro-Ser- Gly (* denotes the attachment site of a polysialoglycan chain). In response to egg activation, PSGP is discharged by exocytosis into the space between the vitelline envelope and the plasma membrane, i.e. the perivitelline space, where the 200-kDa PSGP molecules undergo rapid and dramatic depolymerization by proteolysis into glycotridecapeptides. |
Jiyao W et al.(2023). "The conserved domain database in 2023.",