Structural classification of plant chitinases: two subclasses in class I and class II chitinases

For the classification of plant chitinases, phylogenetic relationships were analyzed besides the established classification of domain structure and C-terminal extension sequences. Two genetically different subclasses (high and low molecular weight) were found for the main structure of class I and class II chitinases in their phylogenetic trees. The genetic distance of these subclasses showed that the high molecular weight subclass may be an ancestral molecule.