A number of plant and fungal proteins that bind N-acetylglucosamine (e.g. solanaceous lectins of tomato and potato, plant class I endochitinases, the wound-induced proteins hevein, win1 and win2, and the Kluyveromyces lactis killer toxin α-subunit) contain a hevein domain, a small domain stabilised by 4 disulfide bonds in one or more copies [1]. The hevein-like domain is thought to be involved in recognition or binding of chitin subunits.
The major latex allergen prohevein (Hev b 6.01) is composed of an N-teminal hevein-like domain and a C-terminal barwin domain. Upon wound-induced coagulation of the latex, the protein is cleaved into its constituent domains. The N-terminal domain, named hevein, contains the major part of the IgE binding sites of prohevein [2]. N-terminal hevein-like domains of class 1 chitinases from fruits such as avocado, banana, and chestnut are cross-reactive with hevein and thought to be responsible for frequent allergic reactions of latex-allergic patients to these fruits termed the latex-fruit syndrome [3]. However, the clinical relevance of IgE cross-reactivity between hevein and class I chitinases has been questioned [4].
An allergen (Bra r 2) with a prohevein-like domain composition was identified in turnip rape [5]. Wheat germ agglutinin (Tri a 18) consists of four hevein-like domains and is an IgE-binding protein of low allergenic significance. Cry j 4, a class IV chitinase from Japanese cedar was shown to bind IgE from a high proportion of patients and cross-reacts with Hevea latex [6].
Family-defining Pfam domains (at least one of these domains is present in each family member):
| Pfam domain | Pfam clan | ||
| PF00182 | Chitinase class I | CL0037 | Lysozyme-like superfamily |
| PF00187 | Chitin recognition protein | - | |
| PF00967 | Barwin family | CL0199 | Double Psi beta barrel glucanase |
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