Binding Site

Legume lectin, beta chain, Mn/Ca-binding site (IPR019825)

Short name: Lectin_legB_Mn/Ca_BS


Lectins are carbohydrate-binding proteins. Leguminous lectins form one of the largest lectin families and resemble each other in their physicochemical properties, though they differ in their carbohydrate specificities. They bind either glucose/mannose or galactose [PMID: 2227211]. Carbohydrate-binding activity depends on the simultaneous presence of both a calcium and a transition metal ion [PMID: 9546043]. The exact function of legume lectins is not known, but they may be involved in the attachment of nitrogen-fixing bacteria to legumes and in the protection against pathogens [PMID: 16441240, PMID: 36624].

Some legume lectins are proteolytically processed to produce two chains, beta (which corresponds to the N-terminal) and alpha (C-terminal) [PMID: 8373823]. The lectin concanavalin A (conA) from jack bean is exceptional in that the two chains are transposed and ligated (by formation of a new peptide bond). The N terminus of mature conA thus corresponds to that of the alpha chain and the C terminus to the beta chain [PMID: 3965973]. Though the legume lectins monomer is structurally well conserved, their quaternary structures vary widely [PMID: 9546043].

The signature pattern for this entry is located in the C-terminal section of the beta chain and contains a conserved aspartic acid residue important for the binding of calcium and manganese.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.
PROSITE patterns