Concanavalin A: Protein Analysis

Each lectin molecule usually comprises of two or more carbohydrate-combining sites, i.e., they are di- or polyvalent. Concanavalin A (a tetramer protein originally extracted from the jack-bean, Canavalia ensiformis) is a member of the legume lectin family and is a particular lectin that has been observed to be able to agglutinate a multitude of cell types, including myocytes, B-lymphocytes and fibroblasts, but for it to perform this action, it needs the presences of sugars which include mannose and glucose monomers. (Hardman and Ainsworth 1972, Loris et al. 1998). It specifically binds α-D-mannosyl and α-D-glucosyl residues in the terminal position of ramified structures from B-Glycans. (Edelman et al. 1972).

Figure 1: Three-dimensional structure of the ConA monomer. (2000)

In …show more content…
Concanavalin and mannose are bound together by H-bonding side chains; asparagine and aspartate. The components of the concanavalin A - Mannose/Glucose pair include concanavalin A, a three dimensional dome shaped monomer consisting of a folded polypeptide backbone governed by two antiparallel pleated sheets, a twisted sheet of seven strands (curved front face) and six (flat back face) strands connected by loops. (Edelman et al. 1972). It also contains the presence of manganese and calcium which are bound to the protein at adjoining sites. Four loops positioned at the upper part of the dome form the monosaccharide-binding site of the lectin monomer that is responsible for the binding of mannose. (Barre et al. 2001).