Carbohydrate binding specificity of the T_n‐antigen binding lectin from Vicia villosa seeds (VVLB₄)

Abstract

-deoxy-D-galaetose (GalNDns) is a useful fluorescent probe to study the interaction of non-fluorescent sugars with tile B4 lectin from Vicia villosa seeds (VVLB4). Binding of the lectin to GalNDns leads to a L2-fold increase in Dansyl fluorescence with a concomitant 10 nm blue shift in its emission maximum. The strong binding of GalNDns (/4, --7.33 × 10 ~ M -~ at 20°C) is due to a favourable entropic contribution to the association process. Among the other sugars studied, GalNAc,rl.O.Ser followed by Mer, GalNAc are the best ligands. 2-Deoxygalaetose, galacto~mine and galactose are 2013, 469 and 130 times weaker ligands, respectively, as compared Io GalNA¢, whereas GalNDns is about 2.44 times more potent than GalNAe. indicating that substitutions at the C-2 position of GalNAc have a considerable influence on the binding affinities. Equatorial orientation of the hydroxyl group at C-3 and axial orientation at C-4 as in galactose are important for the interaction with VVLB4. The C-6 hydroxyl group is not indispensable. The binding site of the leetin is directed exclusively towards monosaccharides alone. Interestingly enough, despite its preference Ibr Me,rGalNAc over MeflGalNAc, in oligosaccharides, the lectin prefers terminal ,8-1inked GaINAc as compared to the ~-linked one.Vicia villosa lectin; 2-Dansylamino-2-deoxy-D-galactose; Monosaccharide binding; Orientation of hydroxyl group

Expression of Vicia villosa agglutinin (VVA)-binding glycoprotein in primary breast cancer cells in relation to lymphatic metastasis: is atypical MUC1 bearing Tn antigen a receptor of VVA?

“…As demonstrated by previous workers and the present study, VVA bound not only to terminal a-linked GalNAc but also to terminal b-linked GalNAc [19]. In addition, VVA can bind to various kinds of GalNAc residues such as Cad antigen, Forssman antigen, GalNac a1 fi 3Gal [18,19,22]. More important, the present study demonstrated that VVA did bind to mannose residues of serotransferrin and that this binding was modulated by formalin fixation.…”

“…This possibility is supported by the fact that VVA specifically recognizes Tn antigen (18)(19)(20)(21)(22)(23). A remaining question concerned the reason why the binding carbohydrate of VVA was not consistent with that of HB-Tn1, although both VVA and HB-Tn1 MAb bind specifically to Tn antigen.…”

“…This work was supported in part by a Grant-in-Aid for Cancer Research [15][16][17][18][19][20][21] from the Ministry of Health, Labour and Welfare of Japan (T.K).…”

“…These studies prompted us to consider that glycoproteins bearing VVA-binding carbohydrates may become an important drug target. However, molecular characterization of glycoproteins in cancer cells has received little attention, although details of exclusive VVAbinding to the Tn antigen (epitope) [N-acetylgalactosamine (GalNAc) 1a-O-serine (Ser)/threonine (Thr)] have been published [18][19][20][21][22][23].…”

Lectin Microarrays for Glycomic Analysis

“…For example, the binding (apparent K d ) of VVL-B4 to a-GalNAc derivatized BSA changed dramatically, by an order of magnitude, from >1,430 nM for 9 ligands per BSA to 129 nM for 13 ligands per BSA. These values and relative affinities are consistent with original studies establishing Tn-antigen (a-GalNAc-Ser) as a specific recognition epitope for VVL-B 4 (Puri et al, 1992).…”