The tomato lectin consists of two homologous chitin-binding modules separated by an extensin-like linker.

A cDNA encoding a putative lectin expressed in tomato leaves was identified and analysed. The lectin consists of two homologous chitin-binding modules interconnected by a short proline-rich domain containing a single Ser[Pro]( n ) repetitive motif. Each module comprises two in-tandem-arrayed hevein domains separated by a tetrapeptide linker. Besides the chitin-binding modules and proline-rich domain, the lectin contains two short unrelated domains located at the N- and C-termini of the protein respectively. Eventual elucidation of the molecular structure of the tomato lectin confirms the presumed chimaeric nature of the Solanaceae lectins but also indicates that all previously proposed models need to be revised.