PROSITE documentation PDOC00025 [for PROSITE entry PS50941]

Chitin-binding type-1 domain signature and profile


Many plants respond to pathogenic attack by producing defense proteins that are capable of reversible binding to chitin, an N-acetylglucosamine polysaccharide present in the cell wall of fungi and the exoskeleton of insects. Most of these chitin-binding proteins include a common structural motif of 30 to 43 residues organized around a conserved four-disulfide core, known as the chitin-binding domain type-1 [1]. The topological arrangement of the four disulfide bonds is shown in the following figure:

                           +----|------+      |
                           |    |      |      |
                  |        ******|*************   |    |
                  |              |                +----+
'C': conserved cysteine involved in a disulfide bond.
'*': position of the pattern.

The structure of several chitin-binding domain type-1 have been solved, (see for example <PDB:1HEV>) [2]. The chitin-binding site is localized in a β-hairpin loop formed by the second disulfide bridge. Conserved serine and aromatic residues associated with the hairpin-loop are essential for the chitin-binding activity [3]. The chitin-binding domain type-1 displays some structural similarities with the chitin-binding domain type-2 (see <PDOC50940>).

Some of the proteins containing a chitin-binding domain type-1 are listed below:

  • A number of non-leguminous plant lectins. The best characterized of these lectins are the three highly homologous wheat germ agglutinins (WGA-1, 2 and 3). WGA is an N-acetylglucosamine/N-acetylneuraminic acid binding lectin which structurally consists of a fourfold repetition of the 43 amino acid domain. The same type of structure is found in a barley root-specific lectin as well as a rice lectin.
  • Plants endochitinases (EC from class IA (see <PDOC00620>). Endochitinases are enzymes that catalyze the hydrolysis of the β-1,4 linkages of N-acetyl glucosamine polymers of chitin. Plant chitinases function as a defense against chitin containing fungal pathogens. Class IA chitinases generally contain one copy of the chitin-binding domain at their N-terminal extremity. An exception is agglutinin/chitinase [4] from the stinging nettle Urtica dioica which contains two copies of the domain.
  • Hevein, a wound-induced protein found in the latex of rubber trees.
  • Win1 and win2, two wound-induced proteins from potato.
  • Kluyveromyces lactis killer toxin α subunit [5]. The toxin encoded by the linear plasmid pGKL1 is composed of three subunits: α, β, and γ. The γ subunit harbors toxin activity and inhibits growth of sensitive yeast strains in the G1 phase of the cell cycle; the α subunit, which is proteolytically processed from a larger precursor that also contains the β subunit, is a chitinase (see <PDOC00839>).

The profile we developed covers the whole domain.


Hevein is a strong allergen which is implied in the allergy to natural rubber latex (NRL). NLR can be associated to hypersensitivity to some plant-derived foods (latex-fruit syndrome). An increasing number of plant sources, such as avocado, banana, chestnut, kiwi, peach, tomato, potato and bell pepper, have been associated with this syndrome. Several papers [6,7] have shown that allergen cross-reactivity is due to IgE antibodies that recognize structurally similar epitopes on different proteins that are closely related. One of these family is plant defence proteins class I chitinase containing a type-1 chitin-binding domain.

Last update:

December 2004 / Pattern and text revised.

Technical section

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

CHIT_BIND_I_2, PS50941; Chitin-binding type-1 domain profile  (MATRIX)

CHIT_BIND_I_1, PS00026; Chitin recognition or binding domain signature  (PATTERN)


1AuthorsWright H.T., Sandrasegaram G., Wright C.S.
TitleEvolution of a family of N-acetylglucosamine binding proteins containing the disulfide-rich domain of wheat germ agglutinin.
SourceJ. Mol. Evol. 33:283-294(1991).
PubMed ID1757999

2AuthorsAndersen N.H., Cao B., Rodriguez-Romero A., Arreguin B.
TitleHevein: NMR assignment and assessment of solution-state folding for the agglutinin-toxin motif.
SourceBiochemistry 32:1407-1422(1993).
PubMed ID8431421

3AuthorsAsensio J.L., Canada F.J., Siebert H.C., Laynez J., Poveda A., Nieto P.M., Soedjanaamadja U.M., Gabius H.J., Jimenez-Barbero J.
TitleStructural basis for chitin recognition by defense proteins: GlcNAc residues are bound in a multivalent fashion by extended binding sites in hevein domains.
SourceChem. Biol. 7:529-543(2000).
PubMed ID10903932

4AuthorsLerner D.R., Raikhel N.V.
TitleThe gene for stinging nettle lectin (Urtica dioica agglutinin) encodes both a lectin and a chitinase.
SourceJ. Biol. Chem. 267:11085-11091(1992).
PubMed ID1375935

5AuthorsButler A.R., O'Donnell R.W., Martin V.J., Gooday G.W., Stark M.J.R.
TitleKluyveromyces lactis toxin has an essential chitinase activity.
SourceEur. J. Biochem. 199:483-488(1991).
PubMed ID2070799

6AuthorsSowka S., Hsieh L.S., Krebitz M., Akasawa A., Martin B.M., Starrett D., Peterbauer C.K., Scheiner O., Breiteneder H.
TitleIdentification and cloning of prs a 1, a 32-kDa endochitinase and major allergen of avocado, and its expression in the yeast Pichia pastoris.
SourceJ. Biol. Chem. 273:28091-28097(1998).
PubMed ID9774427

7AuthorsWagner S., Breiteneder H.
TitleThe latex-fruit syndrome.
SourceBiochem. Soc. Trans. 30:935-940(2002).
PubMed ID12440950

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