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.

Glycosyl hydrolases family 18.

Glyco_18 domain.

The Bacteroides thetaiotaomicron protein represented by pdb structure 3CO4 is an uncharacterized bacterial member of the family 18 glycosyl hydrolases with homologs found in Flavobacterium, Stigmatella, and Pseudomonas.

The GH18 (glycosyl hydrolases, family 18) type II chitinases hydrolyze chitin, an abundant polymer of N-acetylglucosamine and have been identified in bacteria, fungi, insects, plants, viruses, and protozoan parasites. The structure of this domain is an eight-stranded alpha/beta barrel with a pronounced active-site cleft at the C-terminal end of the beta-barrel.

ChainA, CHITINASE 1 [Coccidioides immitis],1LL4_A Chain A, Chitinase 1 [Coccidioides immitis],1LL4_B Chain B, Chitinase 1 [Coccidioides immitis],1LL4_C Chain C, Chitinase 1 [Coccidioides immitis],1LL4_D Chain D, Chitinase 1 [Coccidioides immitis]

ChainA, CHITINASE 1 [Coccidioides immitis],1LL7_B Chain B, CHITINASE 1 [Coccidioides immitis]

Structureof Chitinase 42 from Trichoderma harzianum [Trichoderma harzianum]

Highresoultion crystal structure of human chitinase in complex with allosamidin [Homo sapiens]

CrystalStructure Of Human Chitotriosidase In Complex With Chitobiose [Homo sapiens],1LG2_A Crystal Structure Of Human Chitotriosidase In Complex With Ethylene Glycol [Homo sapiens],1LQ0_A Crystal Structure Of Human Chitotriosidase At 2.2 Angstrom Resolution [Homo sapiens],6ZE8_A Crystal structure of human chitotriosidase-1 (hCHIT) catalytic domain in complex with compound OATD-01 [Homo sapiens],6ZE8_B Crystal structure of human chitotriosidase-1 (hCHIT) catalytic domain in complex with compound OATD-01 [Homo sapiens],6ZE8_C Crystal structure of human chitotriosidase-1 (hCHIT) catalytic domain in complex with compound OATD-01 [Homo sapiens],6ZE8_D Crystal structure of human chitotriosidase-1 (hCHIT) catalytic domain in complex with compound OATD-01 [Homo sapiens],6ZE8_E Crystal structure of human chitotriosidase-1 (hCHIT) catalytic domain in complex with compound OATD-01 [Homo sapiens],6ZE8_F Crystal structure of human chitotriosidase-1 (hCHIT) catalytic domain in complex with compound OATD-01 [Homo sapiens]

Endochitinase 1 OS=Coccidioides posadasii (strain RMSCC 757 / Silveira) OX=443226 GN=CTS1 PE=1 SV=1

Endochitinase 1 OS=Coccidioides immitis (strain RS) OX=246410 GN=CTS1 PE=3 SV=1

Endochitinase 42 OS=Trichoderma harzianum OX=5544 GN=chit42 PE=1 SV=1

Chitinase 4 OS=Candida albicans (strain SC5314 / ATCC MYA-2876) OX=237561 GN=CHT4 PE=3 SV=1

Chitotriosidase-1 OS=Homo sapiens OX=9606 GN=CHIT1 PE=1 SV=1