Purification and Characterization of a Mannose/Glucose‐Specific Lectin from Vicia cracca

Abstract

The seeds of Vicia cracca are known to contain two lectins: an N‐acetylgalactosamine‐binding lectin, which reacts specifically with human erythrocytes of blood group A, and a mannose/glucose‐binding lectin unspecific towards human blood groups. The second lectin is the object of the present work. Purification was achieved by affinity chromatography on Sephadex G‐100. The native lectin has a molecular weight of 44000. It is composed of two small (Mr 5700) and two large subunits (Mr 17500). Binding of sugars to the lectin was assayed by equilibrium dialysis and spectrophotometrically; the association constants for glucose are 1.38×103 l/mol and 2.5×102 l/mol respectively. The primary structure of the small subunit was determined by analyses of the whole chain, of tryptic and CNBr peptides. It was shown to consist of 53 amino acid residues. The mannose/glucose‐binding lectin from Vicia cracca is highly homologous to the lectins from Vicia sativa, Vicia faba, Pisum sativum and Lens culinaris. There is, however, only limited homology to the N‐acetylgalactosamine‐specific lectin from Vicia cracca.

Purification and partial characterization of seed lectins from Vicias belonging to subgenus Vicilla section Cracca

“…Our results showing the presence of single-chain lectins in all of the ten Vicia species that have been studied indicate that single-chain lectins are more common in Tribe Fabeae than previously believed. This does not exclude the potential presence of two-chain lectins in these seeds in lower amounts than single-chain lectins, as has been described in V. cracca (Baumann, Strosberg & Rüdiger, 1982;Rüdiger, 1977). The quaternary structure and molecular weight of the lectins purified from V. cracca and V. villosa are consistent with those previously described (Grubhoffer, Tichá, & Kocourek, 1981;Rüdiger, 1977).…”

“…Sometimes both types of lectins are present in the same species, e.g. lectins in V. cracca (Karhi & Gahmberg, 1980;Baumann, Strosberg & Rüdiger 1982).…”

The amino acid sequences of the α 1 and α 2 subunits of the isoelectins from seeds of Lathyrus ochrus (L) DC

“…Their hemagglutinating activity was inhibited best by D-mannose, D-glucose and their methyl LYglycosides [5]. Antibodies raised in rabbits against the lectins from the genera Pisum [2], Vicia [1, 14,15] and Lens [16], all of which belong to the Vicieae tribe of the family Leguminosae, but much less homology with the region 70-122 of the singlechain lectin Con A [17]. A notable feature of both L. ochrus cy 1 and a2 is that they possessed in positions 14 and 15, instead of aspartic and valine which are invariant in these positions in all of the comparable lectins.…”

The fourth immunoglobulin-like domain of NCAM contains a carbohydrate recognition domain for oligomannosidic glycans implicated in association with L1 and neurite outgrowth.

“…and Vicia cracca (Bauman et al, 1982), was used for this comparison. The fourth immunoglobulin-like domain showed a similarity of 43 % at the protein level to the alpha chain of Lathyrus ochrus lectin (total length 53 amino acids) ( Fig.…”