A major flagellum sialoglycoprotein in sea urchin sperm contains a novel polysialic acid, an alpha2,9-linked poly-N-acetylneuraminic acid chain, capped by an 8-O-sulfated sialic acid residue.
A new type of polysialic acid (polySia) structure was demonstrated to occur in a major unknown sialoglycoprotein with a diverse molecular mass of 40-80 kDa in sea urchin sperm. The polySia-containing glycan structure was determined to be HSO(3)-->8Neu5Acalpha2-->9(Neu5Acalpha2-->9)(n-2) Neu5Acalpha2-->6GalNAcalpha1-->Ser/Thr (n, on average 15), based on carbohydrate analysis of the sialoglycopeptide obtained by an exhaustive protease digestion of whole sperm, fluorometric anion-exchange high-performance liquid chromatography, and methylation analysis. The sulfate group was predominantly localized to the nonreducing terminus of the polySia chain. This is the first example of an alpha2,9-linked polySia structure in animal sperm. The polySia-containing sialoglycoprotein was present in sperm flagellum but not in the head. Furthermore, this sialoglycoprotein localized in the sperm lipid raft, which contains an enriched ganglioside (Neu5Acalpha2-->8Neu5Acalpha2-->6GlcCer), a receptor for sperm-activating peptide (speract), and its associated guanylate cyclase.
Miyata
Shinji
S
Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya 464-8601, Japan.
Sato
Chihiro
C
Kitamura
Shigeyuki
S
Toriyama
Masaru
M
Kitajima
Ken
K
D000818:Animals; D002240:Carbohydrate Sequence; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D002855:Chromatography, Thin Layer; D008297:Male; D008969:Molecular Sequence Data; D019158:N-Acetylneuraminic Acid / Q000737:chemistry*; D012617:Sea Urchins; D013094:Spermatozoa / Q000737:chemistry*
D019158:N-Acetylneuraminic Acid