Home  |  Contact
PROSITE documentation PDOC00278 [for PROSITE entry PS00308]

Legume lectins signatures


Leguminous plants synthesize sugar-binding proteins which are called legume lectins [1,2]. These lectins are generally found in the seeds. 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. Legume lectins bind calcium and manganese (or other transition metals).

Legume lectins are synthesized as precursor proteins of about 230 to 260 amino acid residues. Some legume lectins are proteolytically processed to produce two chains: β (which corresponds to the N-terminal) and α (C-terminal). 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 α chain and the C-terminus to the β chain.

We have developed two signature patterns specific to legume lectins: the first is located in the C-terminal section of the β chain and contains a conserved aspartic acid residue important for the binding of calcium and manganese; the second one is located in the N-terminal of the α chain.

Last update:

December 2004 / Pattern and text revised.

Technical section

PROSITE methods (with tools and information) covered by this documentation:

LECTIN_LEGUME_ALPHA, PS00308; Legume lectins alpha-chain signature  (PATTERN)

LECTIN_LEGUME_BETA, PS00307; Legume lectins beta-chain signature  (PATTERN)


1AuthorsSharon N. Lis H.
TitleLegume lectins--a large family of homologous proteins.
SourceFASEB J. 4:3198-3208(1990).
PubMed ID2227211

2AuthorsLis H. Sharon N.
SourceAnnu. Rev. Biochem. 55:33-37(1986).

PROSITE is copyright. It is produced by the SIB Swiss Institute Bioinformatics. There are no restrictions on its use by non-profit institutions as long as its content is in no way modified. Usage by and for commercial entities requires a license agreement. For information about the licensing scheme send an email to
Prosite License or see: prosite_license.html.


View entry in original PROSITE document format
View entry in raw text format (no links)