Structural similarity of plant chitinase and lysozymes from animals and phage. An evolutionary connection.

A search in the database of known three-dimensional protein structures with the structure of a plant endochitinase revealed a subtle but unambiguous similarity to lysozymes from animals and phages. An evolutionary connection between plant endochitinases and lysozymes is supported by similar overall topology of fold, overlapping substrate specificities and remarkable conservation of some sequence and architectural detail around the active site. Much of the knowledge about lysozyme can now be extended by analogy to endochitinase. New insights into the mechanism of endochitinase are expected to stimulate genetic engineering studies into plant defense mechanisms against pests and pathogens.