Fuc-TIX: a versatile alpha1,3-fucosyltransferase with a distinct acceptor- and site-specificity profile

Glycobiology. 2002 Jun;12(6):361-8. doi: 10.1093/glycob/12.6.361.

Abstract

alpha1,3-Fucosyltransferases (Fuc-Ts) convert N-acetyllactosamine (LN, Galbeta1-4GlcNAc) to Galbeta1-4(Fucalpha1-3)GlcNAc, the Lewis x (CD15, SSEA-1) epitope, which is involved in various recognition phenomena. We describe details of the acceptor specificity of alpha1,3-fucosyltransferase IX (Fuc-TIX). The unconjugated N- and O-glycan analogs LNbeta1-2Man, LNbeta1-6Manalpha1-OMe, LNbeta1-2Manalpha1-3(LNbeta1-2Manalpha1-6)Manbeta1-4GlcNAc, and Galbeta1-3(LNbeta1-6)GalNAc reacted well in vitro with Fuc-TIX present in lysates of appropriately transfected Namalwa cells. Fuc-TIX reacted well with the reducing end LN of GlcNAcbeta1-3'LN (underscored site reacted) and GlcNAcbeta1-3'LNbeta1-3'LN (both LNs reacted), but very poorly with the reducing end LN of LNbeta1-3'LN. However, Fuc-TIX reacted significantly better with the non-reducing end LN as compared to the other LN units in the glycans LNbeta1-3'LN and LNbeta1-3'LNbeta1-3'LNbeta1-3'LN, confirming our previous data on LNbeta1-3'LNbeta1-OR. In contrast, the sialylated glycan Neu5Acalpha2-3'LNbeta1-3'LNbeta1-3'LNbeta1-3'LN was fucosylated preferentially at the two most reducing end LN units. We conclude that Fuc-TIX is a versatile alpha1,3-Fuc-T, that (1) generates distal Lewis x epitopes from many different acceptors, (2) possesses inherent ability for the biosynthesis of internal Lewis x epitopes on growing polylactosamine backbones, and (3) fucosylates the remote internal LN units of alpha2,3-sialylated i-type polylactosamines.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Sugars / metabolism
  • Animals
  • Binding Sites
  • Carbohydrate Sequence
  • Cell Line
  • Cricetinae
  • Disaccharides / metabolism
  • Fucosyltransferases / chemistry*
  • Fucosyltransferases / genetics
  • Fucosyltransferases / metabolism*
  • Humans
  • Molecular Sequence Data
  • Polysaccharides / metabolism*
  • Substrate Specificity
  • Trisaccharides / metabolism

Substances

  • Amino Sugars
  • Disaccharides
  • Polysaccharides
  • Trisaccharides
  • polylactosamine
  • Fucosyltransferases
  • galactoside 3-fucosyltransferase