PROSITE documentation PDOC50228
SUEL-type lectin domain profile


Lectins bind to specific carbohydrate residues of glycoproteins and glycolipids present at the cell surface. This allow them to agglutinate a variety of cellular types. On the basis of sequence similarity and common characteristics such as sugar binding specificity, conserved carbohydrate recognition domains, and ion requirement the different lectins can be grouped in different categories, like C-type, I-type, galectins, pentraxins and P-type lectin.

The sea urchin (Anthocidaris crassispina) egg lectin (SUEL) forms a new class of lectins. Altough SUEL was first isolated as a D-galactoside binding lectin it was latter shown that it bind to L-rhamnose preferentially [1,2]. L-rhamnose and D-galactose share the same hydroxyl group orientation at C2 and C4 of the pyranose ring structure. SUEL is a lectin that exist as a disulfide linked homodimer. The dimeric form is essential for hemagglutination activity but the monomeric form retains carbohydrate binding capacity [1]. Based on primary structure analysis, a cysteine-rich domain homologous to the SUEL protein has been identified in the following proteins [3,4,5]:

  • Plant β-galactosidases (EC (lactases). They constitute a widespread family of enzymes characterized by their ability to hydrolyse terminal, non-reducing β D-galactosyl residues from β-D-galactosides.
  • Mammalian latrophilin, the calcium independent receptor of α- latrotoxin (CIRL). It belongs to the secretin family of G-protein coupled receptors. The lectin domain is not required for α-latratoxin binding [5].
  • Human lectomedin-1.
  • Rhamnose-binding lectin (SAL) from catfish (Parasilurus asotus) eggs. This protein is composed of three tandem repeat domains homologous to the SUEL lectin domain. All cysteine positions of each domain are completely conserved [2].
  • Caenorhabditis elegans hypothetical proteins B0457.1, F32A7.3A and F32A7.3B.
  • Human hypothetical protein KIAA0821.
Last update:

December 2001 / First entry.


Technical section

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

SUEL_LECTIN, PS50228; SUEL-type lectin domain profile  (MATRIX)


1AuthorsOzeki Y. Matsui T. Suzuki M. Titani K.
TitleAmino acid sequence and molecular characterization of a D-galactoside-specific lectin purified from sea urchin (Anthocidaris crassispina) eggs.
SourceBiochemistry 30:2391-2394(1991).
PubMed ID2001368

2AuthorsHosono M. Ishikawa K. Mineki R. Murayama K. Numata C. Ogawa Y. Takayanagi Y. Nitta K.
TitleTandem repeat structure of rhamnose-binding lectin from catfish (Silurus asotus) eggs.
SourceBiochim. Biophys. Acta 1472:668-675(1999).
PubMed ID10564781

3AuthorsLelianova V.G. Davletov B.A. Sterling A. Rahman M.A. Grishin E.V. Totty N.F. Ushkaryov Y.A.
TitleAlpha-latrotoxin receptor, latrophilin, is a novel member of the secretin family of G protein-coupled receptors.
SourceJ. Biol. Chem. 272:21504-21508(1997).
PubMed ID9261169

4AuthorsTateno H. Saneyoshi A. Ogawa T. Muramoto K. Kamiya H. Saneyoshi M.
TitleIsolation and characterization of rhamnose-binding lectins from eggs of steelhead trout (Oncorhynchus mykiss) homologous to low density lipoprotein receptor superfamily.
SourceJ. Biol. Chem. 273:19190-19197(1998).
PubMed ID9668106

5AuthorsKrasnoperov V. Bittner M.A. Holz R.W. Chepurny O. Petrenko A.G.
TitleStructural requirements for alpha-latrotoxin binding and alpha-latrotoxin-stimulated secretion. A study with calcium-independent receptor of alpha-latrotoxin (CIRL) deletion mutants.
SourceJ. Biol. Chem. 274:3590-3596(1999).
PubMed ID9920906

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