Site-specific Fucosylation of Sialylated Polylactosamines by α1,3/4-Fucosyltransferases-V and -VI Is Defined by Amino Acids Near the N Terminus of the Catalytic Domain*

  title={Site-specific Fucosylation of Sialylated Polylactosamines by $\alpha$1,3/4-Fucosyltransferases-V and -VI Is Defined by Amino Acids Near the N Terminus of the Catalytic Domain*},
  author={Susan Shetterly and Franziska Jost and Susan R. Watson and Ronald M. A. Knegtel and Bruce Macher and Eric H. Holmes},
  journal={Journal of Biological Chemistry},
  pages={24882 - 24892}
Fucose transfer from GDP-fucose to GlcNAc residues of the sialylated polylactosamine acceptor NeuAcα2-3Galβ1-4Glc-NAcβ1-3Galβ1-4GlcNAcβ1-3Galβ1-4Glcβ1-ceramide leads to two isomeric monofucosyl antigens, VIM2 and sialyl-Lex. Human α1,3/4-fucosyltransferase (FucT)-V catalyzes primarily the synthesis of VIM2, whereas human FucT-VI catalyzes primarily the synthesis of sialyl-Lex. Thus, these two enzymes have distinct “site-specific fucosylation” properties. Amino acid sequence alignment of these… 
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Human alpha1,3/4-fucosyltransferases. II. A single amino acid at the COOH terminus of FucT III and V alters their kinetic properties.
Results demonstrate that substitution of an acidic amino acid for a nonpolar amino acid at the COOH terminus of FucTs produces an enzyme with enhanced enzyme activities, and provide new insights into the structure/function relationships of human alpha1,3/4-FucT enzymes.
Specificity of fucose transfer to GlcNAc residues of extended chain neolacto-series glycolipids catalyzed by human alpha 1-->3fucosyltransferases: effect of the lipidic environment on the myeloid enzyme form.
The results indicate that subtle intrinsic differences exist between human alpha 1-->3fucosyltransferases and Modulation of enzyme specificity via the nature of the membrane environment could participate in regulation of expression of distinct cell surface antigens.
A GDP-fucose-protected, pyridoxal-5'-Phosphate/NaBH(4)-sensitive lys residue common to human alpha1-->3Fucosyltransferases corresponds to Lys(300) in FucT-IV.
Of three conserved lysines in FucT-IV, two (Lys(228) and Lys(283)) are not involved in substrate binding but perhaps in catalysis, and the third site, Lys(300), is involved in GDP-fucose binding and PLP/NaBH(4) inactivation.
The acceptor and site specificity of alpha 3-fucosyltransferase V. High reactivity of the proximal and low of the distal galbeta 1-4GlcNAc unit in i-type polylactosamines.
The data show that Fuc-TV worked well with a very wide range of LN-glycans, showing weak reactivity only with distal (sialyl)LN units of i-type polylactosamines, biantennary N-glyCans, and I branches of polylACTosamines.
Human α1,3/4-Fucosyltransferases
Amino acid sequence alignment of human α1,3/4-fucosyltransferases (FucTs) demonstrates that three highly conserved Lys residues are present in the catalytic domain of FucTs III, IV, V, and VI. Two of
Structure-function analysis of human alpha1,3-fucosyltransferase. Amino acids involved in acceptor substrate specificity.
Results obtained from domain swapping experiments demonstrated that the single amino acid sequence difference near the C terminus of these enzymes did not alter the enzyme's substrate specificity, however, swapping a region near the N termini of the truncated form of FucT III into an homologous region in Fuc T V produced a protein with both alpha1,3- andalpha1,4-fucosyltransferase activity.
Human alpha1,3/4-fucosyltransferases. I. Identification of amino acids involved in acceptor substrate binding by site-directed mutagenesis.
Results demonstrate that amino acid residues near the amino terminus of the catalytic domain of FucT III contribute to its acceptor substrate specificity.
Enzymatic synthesis of α3′sialylated and multiply α3fucosylated biantennary polylactosamines
Multifucosylated sialo-polylactosamines are known to be high affinity ligands for E-selectin. PSGL-1, the physiological ligand of P-selectin, is decorated in HL-60 cells by a sialylated and triply
Structure-function analysis of human alpha 1-->3fucosyltransferases. A GDP-fucose-protected, N-ethylmaleimide-sensitive site in FucT-III and FucT-V corresponds to Ser178 in FucT-IV.
Modification of FucT-V by 5,5'-dithiobis(2-nitrobenzoic acid) resulted in efficient enzyme inactivation that could be reversed by excess thiol reagent suggesting that the free sulfhydral group on the enzyme was required for activity.
Structure/function study of Lewis alpha3- and alpha3/4-fucosyltransferases: the alpha1,4 fucosylation requires an aromatic residue in the acceptor-binding domain.
The optimal fucose addition in alpha1,3 linkage requires the R residue in the acceptor-binding motif of Lewis FUTs, and the ability of alpha3/4-FUTs to recognize type 1 substrates involves the aromatic character of W in the acceptance-binding domain.