Intrinsic fluorescence studies on saccharide binding toArtocarpus integrifolialectin

Abstract

The combining region of Artocarpus integrifolia lectin has been studied by using the ligand-induced changes in the fluorescence of the lectin. The saccharide binding properties of the lectin show that C-1, C-2, C-4, and C-6 hydroxyl groups of D-galactose are important loci for sugar binding. The alpha-anomer of galactose binds more strongly than its beta-counterpart. Inversion in the configuration at C-4 as in glucose results in a loss of binding to the lectin. The C-6 hydroxyl group is also presumably involved in binding as D-fucose does not bind to the lectin. The lectin binds to the Thomsen-Friedenreich antigen (Gal beta(1----3)GalNAc) more strongly than the other disaccharides studied, viz. Gal beta (1----4) Gal and Gal beta (1----3) GlcNAc, which are topographically similar to T-antigen. This observation suggests that the combining region of Artocarpus lectin is complementary to that of T-antigen. Solvent accessibility of the protein fluorophores have been probed by the quenching of protein fluorescence by Iodide ion in the absence and presence of sugar. In the presence of sugar a slight inaccessibility of the fluorophores to the solvent has been observed.

Simian Immunodeficiency Virus from the Sooty Mangabey and Rhesus Macaque Is Modified with O-Linked Carbohydrate

“…Lectin protein from jackfruit seeds (jacalin) binds with a primary specificity to non-and monosialylated core 1 (Gal␤-1,3GalNAc-␣) O-linked carbohydrate (26,42,48,53). To determine if SIVmac239 is sensitive to jacalin, the replication of SIVmac239 was assayed at a low multiplicity of infection under conditions of a spreading infection.…”

“…It remains possible that HIV-1 gp120 is modified with mucin-type O-linked carbohydrate to which jacalin and PNA do not bind. Jacalin binds the Tn antigen, core 1, and monosialylated core 1 mucin-type carbohydrate (26,42,48,53). PNA binds to nonsialylated core 1 carbohydrate (31,35,47,54).…”

“…Plant lectin proteins from jackfruit seeds (jacalin) and peanuts (peanut agglutinin [PNA]) are generally regarded to have primary specificity toward nonsialylated core 1 (Gal␤-1,3GalNAc-␣) Olinked carbohydrate (26,31,42). Jacalin also binds the Tn antigen and monosialylated core 1 carbohydrate (48,53).…”

Structural basis for the unusual carbohydrate-binding specificity of jacalin towards galactose and mannose

“…The carbohydrate-binding specificity of jacalin has been studied intensively since the discovery of its specific interaction with IgA1 [8] and the Thomsen-Friedenreich or T-antigen disaccharide Galβ1,3GalNAc [9]. Measurements of the intrinsic fluorescence of excited jacalin in the presence of various sugars indicated that -galactose, β-Met-Gal and 2-deoxy-α--galactose are the most potent inhibitors of the lectin [10]. Hapten inhibition of the agglutination of IgA1-coated latex particles by simple sugars and sugar derivatives demonstrated further that the inhiAbbreviations used : Heltuba, Helianthus tuberosus agglutinin ; HBS, Hepes-buffered saline ; MPA, Maclura pomifera agglutinin ; Neu5Ac, N-acetylneuraminic acid ; MurNAc, N-acetylmuramic acid ; SPR, surface plasmon resonance.…”

T-antigen (Gal β3 GaINAc α-) containing glycoproteins of human reace

“…The jacalinglycoprotein interaction was found to be sugar specific as it could be inhibited in the presence of 0.1M galactose. Investigations of jacalin's ligand specificity revealed its high affinty for ec-galactopyranosides and particularly for the T-antigen with the structure, 1-J~-D-galactopyra nosyl-3-(o~-2-acetamido-2-deoxygalactopyranoside) (13,14). Jacalin recognizes the T-antigenic structure on glycoproteins even when substituted with a terminal sialic acid residue (15).…”