ISSN:
1573-4986
Keywords:
Haemonchus contortus
;
α1,3-fucosyltransferase
;
Lex antigen
;
β1,4-galactosyltransferase
;
β1,4-N-acetylgalactosaminyltransferase
;
NDV, New Castle Disease
;
WFA, Wisteria floribunda agglutinin
;
LTA, Lotus tetragonolobus agglutinin
;
NEM, N-ethylmaleimide
;
Lea, Lewis a antigen
;
Lex, Lewis x antigen
;
sLex, sialyl Lewis x
;
Ley, Lewis y antigen
;
SDS-PAGE, sodium dodecyl
;
PBS, phosphate buffered saline
;
TTBS, Tween-20/Tris buffered saline
;
EDTA, ethylenediaminetetraacetic acid
;
PMSF, phenylmethylsulfonyl fluoride
;
BCA, bicinchoninic acid
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Glycoproteins from the ruminant helminthic parasite Haemonchus contortus react with Lotus tetragonolobus agglutinin and Wisteria floribunda agglutinin, which are plant lectins that recognize α1,3-fucosylated GlcNAc and terminal β-GalNAc residues, respectively. However, parasite glycoconjugates are not reactive with Ricinus communis agglutinin, which binds to terminal β-Gal, and the glycoconjugates lack the Lewis x (Lex) antigen or other related fucose-containing antigens, such as sialylated Lex, Lea, Leb Ley, or H-type 1. Direct assays of parasite extracts demonstrate the presence of an α1,3-fucosyltransferase (α1,3FT) and β1,4-N-acetylgalactosaminyltransferase (β1,4GalNAcT), but not β1,4-galactosyltransferase. The H. contortus α1,3FT can fucosylate GlcNAc residues in both lacto-N-neotetraose (LNnT) Galα1→4GlcNAcβ1→3Galβ1→4Glc to form lacto-N-fucopentaose III Galβ1→ 4[Fucα1→3]GlcNAcβ1→3Galβ1→4Glc, which contains the Lex antigen, and the acceptor lacdiNAc (LDN) GalNAcβ1→4GlcNAc to form GalNAcβ1→4[Fucα1 →3]GlcNAc. The α1,3FT activity towards LNnT is dependent on time, protein, and GDP-Fuc concentration with a Km 50 μ M and a Vmax of 10.8 nmol-mg−1 h−1. The enzyme is unusually resistant to inhibition by the sulfhydryl-modifying reagent N-ethylmaleimide. The α1,3FT acts best with type-2 glycan acceptors (Galβ1→4GlcNAcβ1-R) and can use both sialylated and non-sialylated acceptors. Thus, although in vitro the H. contortus α1,3FT can synthesize the Lex antigen, in vivo the enzyme may instead participate in synthesis of fucosylated LDN or related structures, as found in other helminths.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1006912032273
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