A proline-rich chitinase from Beta vulgaris.

A gene (Ch1) encoding a novel type of chitinase was isolated from Beta vulgaris. The Ch1 protein consists of an N-terminal hydrophobic prepeptide of 25 amino acids followed by a hevein-like domain of 22 amino acid residues, an unusually long proline-rich domain of 131 amino acid residues with 90 prolines, and finally a catalytic domain of 261 amino acid residues. Proteins with similar proline-rich domains are present in some other plants. The Ch1 gene shows a transient expression in response to fungal infection.