Branching and elongation with lactosaminoglycan chains of N‐linked oligosaccharides result in a shift toward termination with α2→3‐linked rather than with α2→6‐linked sialic acid residues

FEBS Letters

Nemansky, Martin¹  Schiphorst, Wietske E.C.M.¹  Van den Eijnden, Dirk H.¹ 

[1] Department of Medical Chemistry, Vrije Universiteit, Van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands

关键词: N-glycan branching;    Oligosaccharide;    Lactosaminoglycan;    Sialylation;    Sialytransferase;    CMP-NeuAc;    Cytidine 5′-monophospho-N-acetylneuraminic acid;    NeuAc;    N-acetylneuraminic acid;    GalT;    galactosyltransferase;    GlcNacT;    N-acetylglucosaminyltransferase;    α6-NeuAcT;    CMP-NeuAc:Galβ1→4GlcNAcβ-R α2→6-sialyltransferase (EC 2.4.99.1);    α3-NeuAcT;    CMP-NeuAc:Galβ1→4rmGlcNAcβ-R α→3- fsialyltransferase (EC 2.4.99.6);   

DOI  :  10.1016/0014-5793(95)00336-8

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The activity of bovine colostrum CMP-NeuAc: Galβ1→4GlcNAcβ-R α2→6-sialyltransferase (α6-NeuAcT) toward oligosaccharides that form part of complex-type, N-linked glycans appears significantly reduced when a bisecting GlcNAc residue or additional branches are present, or when core GlcNAc residues are absent. By contrast human placenta CMP-NeuAc:Galβ1→4GlcNAcβ-Rα2→3-sialyltransferase (α3-NeuAcT) is much less sensitive to structural variations in these acceptors. Furthermore the α3-NeuAcT shows a much higher activity than the α6-NeuAcT with oligosaccharides that form part of linear and branched lactosaminoglycan extensions. These results indicate that, in tissues that express both enzymes, branching and lactosaminoglycan formation of N-linked glycans will cause a shift from termination with α2→6-linked sialic acid to termination with α2→3-linked sialic acid residues. These findings provide an enzymatic basis for the sialic acid linkage-type patterns found on the oligosaccharide chains of N-glycoproteins.

【 授权许可】

Unknown