Protein which binds chitin, a linear polysaccharide consisting of (1->4)-beta-linked D-glucosamine residues, most of which are N-acetylated. The 30-43 amino acids long chitin-binding domain contains several conserved glycine and cysteines residues. The conserved cysteines form disulfide bonds. Chitin-binding domains have been found in plant, fungal and bacterial proteins.