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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.

December 2004 / Pattern and text revised.

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

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

Consensus pattern: [LIV]-{LA}-[EDQ]-[FYWKR]-V-{VF}-[LIVF]-G-[LF]-[ST] Sequences known to belong to this class detected by the pattern: ALL Other sequence(s) detected in Swiss-Prot: 8.

• Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS00308 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS00308 • Scan Swiss-Prot/TrEMBL entries against PS00308 • view ligand binding statistics

Matching PDB structures: 1APN 1AVB 1AX0 1AX1 ... [ALL]

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

Consensus pattern: [LIV]-[STAG]-V-[DEQV]-[FLI]-D-[ST] D binds manganese and calcium Sequences known to belong to this class detected by the pattern: ALL Other sequence(s) detected in Swiss-Prot: 46.

• Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS00307 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS00307 • Scan Swiss-Prot/TrEMBL entries against PS00307 • view ligand binding statistics

Matching PDB structures: 1APN 1AVB 1AX0 1AX1 ... [ALL]

1	Authors	Sharon N., Lis H.
	Title	Legume lectins--a large family of homologous proteins.
	Source	FASEB J. 4:3198-3208(1990).
	PubMed ID	2227211

2	Authors	Lis H., Sharon N.
	Source	Annu. Rev. Biochem. 55:33-37(1986).

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