PF-ChiA is an uncharacterized chitinase found in the hyperthermophilic archaeon Pyrococcus furiosus with a glycosyl hydrolase family 18 (GH18) catalytic domain as well as a cellulose-binding domain. Members of this domain family are found not only in archaea but also in eukaryotes and prokaryotes. PF-ChiA exhibits hydrolytic activity toward both colloidal and crystalline (beta/alpha) chitins at high temperature.

Chitin-binding domain of chitinase C. Chitin-binding domain of chitinase C (ChiC) of Streptomyces griseus and related proteins. Chitinase C is a family 19 chitinase, and consists of a N-terminal chitin binding domain and a C-terminal chitin-catalytic domain that effects degradation. Chitinases function in invertebrates in the degradation of old exoskeletons, in fungi to utilize chitin in cell walls, and in bacteria which use chitin as an energy source. ChiC contains the characteristic chitin-binding aromatic residues.

The GH18 (glycosyl hydrolase, family 18) type II chitinases hydrolyze chitin, an abundant polymer of beta-1,4-linked N-acetylglucosamine (GlcNAc) which is a major component of the cell wall of fungi and the exoskeleton of arthropods. Chitinases have been identified in viruses, bacteria, fungi, protozoan parasites, insects, and plants. The structure of the GH18 domain is an eight-stranded beta/alpha barrel with a pronounced active-site cleft at the C-terminal end of the beta-barrel. The GH18 family includes chitotriosidase, chitobiase, hevamine, zymocin-alpha, narbonin, SI-CLP (stabilin-1 interacting chitinase-like protein), IDGF (imaginal disc growth factor), CFLE (cortical fragment-lytic enzyme) spore hydrolase, the type III and type V plant chitinases, the endo-beta-N-acetylglucosaminidases, and the chitolectins. The GH85 (glycosyl hydrolase, family 85) ENGases (endo-beta-N-acetylglucosaminidases) are closely related to the GH18 chitinases and are included in this alignment model.

GH18 domain of Chitinase D (ChiD). ChiD, a chitinase found in Bacillus circulans, hydrolyzes the 1,4-beta-linkages of N-acetylglucosamine in chitin and chitodextrins. The domain architecture of ChiD includes a catalytic glycosyl hydrolase family 18 (GH18) domain, a chitin-binding domain, and a fibronectin type III domain. The chitin-binding and fibronectin type III domains are located either N-terminal or C-terminal to the catalytic domain. This family includes exochitinase Chi36 from Bacillus cereus.

Crystalstructure of catalytic domain of hyperthermophilic chitinase from Pyrococcus furiosus [Pyrococcus furiosus],2DSK_B Crystal structure of catalytic domain of hyperthermophilic chitinase from Pyrococcus furiosus [Pyrococcus furiosus]

Crystalstructures of catalytic site mutants of active domain 2 of thermostable chitinase from Pyrococcus furiosus complexed with chito-oligosaccharides [Pyrococcus furiosus],3A4W_B Crystal structures of catalytic site mutants of active domain 2 of thermostable chitinase from Pyrococcus furiosus complexed with chito-oligosaccharides [Pyrococcus furiosus]

Crystalstructures of catalytic site mutants of active domain 2 of thermostable chitinase from Pyrococcus furiosus complexed with chito-oligosaccharides [Pyrococcus furiosus],3A4X_B Crystal structures of catalytic site mutants of active domain 2 of thermostable chitinase from Pyrococcus furiosus complexed with chito-oligosaccharides [Pyrococcus furiosus],3AFB_A Crystal structures of catalytic site mutants of active domain 2 of chitinase from Pyrococcus furiosus [Pyrococcus furiosus],3AFB_B Crystal structures of catalytic site mutants of active domain 2 of chitinase from Pyrococcus furiosus [Pyrococcus furiosus]

Probable bifunctional chitinase/lysozyme OS=Escherichia coli (strain K12) OX=83333 GN=chiA PE=1 SV=2

Endochitinase 11 OS=Metarhizium anisopliae OX=5530 GN=chi11 PE=1 SV=1