Occurrence of terminal α2 → 8-linked disialylated poly-N-acetyllactosamine chains with Le(X) and I antigenic glycotopes in tetraantennary arms of an N-linked glycoprotein isolated from rainbow trout ovarian fluid

Yoko Funakoshi, Tomohiko Taguchi, Chihiro Sato, Ken Kitajima, Sadako Inoue, Howard R. Morris, Anne Dell, Yasuo Inoue

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The Pronase digestion of a 54K glycoprotein present in ovarian fluid of rainbow trout yielded a major glycopeptide. Carbohydrate compositional analysis revealed that this glycopeptide was likely to possess a single large N-glycan chain having low molecular weight oligomers of N-acetylneuraminic acid (oligoNeu5Ac). Structural studies of this glycopeptide revealed novel α2 → 8-linked disialylated poly-N-acetyllactosamine chains with Le(X) and I antigenic determinants on the N-linked tetraantennary core glycan. In our recent studies (Kitazume, S., Kitajima, K., Inoue, S., Inoue, Y. and Troy, F.A. (1994) J. Biol. Chem. 269, 10330-10340) we presented evidence that synthesis of α2 → 8-linked polysialic acid (polySia) chains is a two-step process in which chain initiation is catalyzed by an α2 → 8-sialyltransferase (α2 → 8-ST; initiase) that catalyzes synthesis of the first Sia α2 → 8-linkage, forming the disialic acid (diSia) unit, Siaα2 → 8-Siaα2 → 6-Gal-.Chain polymerization is then postulated to be catalyzed by a second enzyme, an α2 → 8-polyST ('polymerase') that converts the diSia units to polySia chains. The present structural studies leading to the discovery of α2 → 8-linked disialylated units that terminate poly-N-acetyllactosamine chains in an N-linked glycoprotein is further evidence in support of our hypothesis that more than one sialyltransferase activity is required for polySia chain synthesis and polymerization.

Original languageEnglish
Pages (from-to)195-205
Number of pages11
JournalGlycobiology
Volume7
Issue number2
DOIs
Publication statusPublished - 1997 Mar 1
Externally publishedYes

Keywords

  • Disialosyl group
  • I antigen
  • Le(X) antigen
  • Poly-N-acetyllactosamine
  • Tetraantennary N-glycan

ASJC Scopus subject areas

  • Biochemistry

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