Specificity analysis of three clonal and five non-clonal α1,3-L- fucosyltransferases with sulfated, sialylated, or fucosylated synthetic carbohydrates as acceptors in relation to the assembly of 3'-sialyl-6'-sulfo Lewis x (the L-selectin ligand) and related complex structures

Unique specificities of the cloned α1,3-L-fucosyltransferases (FTs), FT III (Lewis type), FT IV (myeloid type), and FT V (plasma type), and the α1,3-FTs of Colo 205 (colon carcinoma), HL 60 (myeloid), B142 (lymphoid), EKVX (lung carcinoma), and calf mesenteric lymph nodes (CMLN) were discerned with sulfated, sialylated, and/or fucosylated Galβ1,3/4GlcNAcβ-based acceptor moieties. (a) FT V was 1.0-, 20.8-, and 4.6-fold active in forming Lewis x, Lewis y, and 3'-α-galactosyl Lewis x, respectively. (b) FT III and FT V formed ~4-fold 3'-sulfo Lewis x, as compared to 3'-sialyl Lewis x. (c) FT IV showed great efficiency in forming 3'-sulfo Lewis x (249%) and Lewis x (345%) in mucin-type branched chains. (d) FT III, FT IV, and FT V formed 19%, 62%, and 47% 6-sulfo Lewis x as compared to Lewis x. (e) 6'-Sulfo Lewis x and 3'-sialyl-6'-sulfo Lewis x (GLYCAM ligand) were not synthesized from their immediate precursors by FT III, FT IV, or FT V. (f) FT III, FT IV, and FT V were 311%, 9%, and 188% active, respectively, with 2'-fucosyl lactose but were not active with 2'-fucosyl-6'-sulfo lactose. (g) FT III and FT V were 7.0- and 0.5-fold active in forming Lewis a as compared to Lewis x, whereas, FT IV was inactive. (h) FT III was -2.0-fold more active in forming 3'-α- galactosyl Lewis a than Lewis b. (i) FT III synthesized 6-sialyl Lewis a (40% efficiency as compared to Lewis a) from 6-sialyl type 1. (j) FT III did not act on 6'-sulfo or 6'-sialyl type I but was 106% and 22% active with 3'- sulfo and 6-sulfo type I, respectively. (k) The Colo 205 FT activities with type I compounds almost paralleled that of FT III except for the low activity (9%) with Galβ1,3(NeuAcα2, 6)GlcNAcβ-O-Bn, but with type 2 considerable differences between Colo 205 FT and FT III were noticed. (1) The α1,3-FTs of CMLN, HL60, B142, and EKVX were 1.2-1.7 times active with Fucα1,2Galβ1,4GlcNAcβ-O-pNP and Galα1,3Galβ1,4GlcNAcβ-O-Bn with respect to Galβ1,4GlcNAcβ-O-A1. (m) Both CMLN and HL60 FTs were 2-fold active with 3-sulfoGalβ1,4GlcNAc in a mucin-type branch structure such as 3- sulfoGalβ1,4GlcNAcβ1,6(Galβ1,3)GalNAcα-O-Bn. (n) The 3'- sulfoLacNAc/acrylamide copolymer, either as an acceptor or as a competitive inhibitor, had the potential to distinguish myeloid type α1,3-FT from the plasma type.