Glycoside hydrolase family 19, chitinase domain. Chitinases are enzymes that catalyze the hydrolysis of the beta-1,4-N-acetyl-D-glucosamine linkages in chitin polymers. Glycoside hydrolase family 19 chitinases are found primarily in plants (classes I, III, and IV), but some are found in bacteria. Class I and II chitinases are similar in their catalytic domains. Class I chitinases have an N-terminal cysteine-rich, chitin-binding domain which is separated from the catalytic domain by a proline and glycine-rich hinge region. Class II chitinases lack both the chitin-binding domain and the hinge region. Class IV chitinases are similar to class I chitinases, but they are smaller in size due to certain deletions. Despite lacking any significant sequence homology with lysozymes, structural analysis reveals that family 19 chitinases, together with family 46 chitosanases, are similar to several lysozymes including those from T4-phage and from goose. The structures reveal that the different enzyme groups arose from a common ancestor glycohydrolase antecedent to the prokaryotic/eukaryotic divergence.

Chitinase class I.

Domain of unknown function (DUF5011). This small family of proteins is functionally uncharacterized. This family is found in Bacteroides, Prevotella, and Parabateroides. Proteins in this family are around 230 amino acids in length.

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.

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.

ChainA, GH19 Chitinase [Ficus microcarpa],7V91_B Chain B, GH19 Chitinase [Ficus microcarpa],7V91_C Chain C, GH19 Chitinase [Ficus microcarpa],7V91_D Chain D, GH19 Chitinase [Ficus microcarpa]

CrystalStructure of GH family 19 chitinase from Carica papaya [Carica papaya],3CQL_B Crystal Structure of GH family 19 chitinase from Carica papaya [Carica papaya]

ChainA, GH19 Chitinase [Ficus microcarpa],7V92_B Chain B, GH19 Chitinase [Ficus microcarpa],7V92_C Chain C, GH19 Chitinase [Ficus microcarpa],7V92_D Chain D, GH19 Chitinase [Ficus microcarpa]

Structureof the chitinase from jack bean [Canavalia ensiformis]

Structureof intact chitinase with hevein domain from the plant Simarouba glauca, known for its traditional anti-inflammatory efficacy [Simarouba glauca]

Chitinase 9 OS=Oryza sativa subsp. japonica OX=39947 GN=Cht9 PE=2 SV=1

Basic endochitinase (Fragment) OS=Solanum lycopersicum OX=4081 GN=CHI14 PE=2 SV=1

Basic 30 kDa endochitinase OS=Solanum lycopersicum OX=4081 GN=CHI9 PE=1 SV=1

Endochitinase OS=Actinidia chinensis var. chinensis OX=1590841 GN=CEY00_Acc04863 PE=1 SV=2

Endochitinase OS=Persea americana OX=3435 GN=chi1 PE=1 SV=2