Glyco_18 domain.

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.

Chitinase, GH18 family [Carbohydrate transport and metabolism].

Glycosyl hydrolases family 18.

This conserved domain family includes a large number of catalytically inactive chitinase-like lectins (chitolectins) including YKL-39, YKL-40 (HCGP39), YM1, oviductin, and AMCase (acidic mammalian chitinase), as well as catalytically active chitotriosidases. The conserved domain is an eight-stranded alpha/beta barrel fold belonging to the family 18 glycosyl hydrolases. The fold has a pronounced active-site cleft at the C-terminal end of the beta-barrel. The chitolectins lack a key active site glutamate (the proton donor required for hydrolytic activity) but retain highly conserved residues involved in oligosaccharide binding. Chitotriosidase is a chitinolytic enzyme expressed in maturing macrophages, which suggests that it plays a part in antimicrobial defense. Chitotriosidase hydrolyzes chitotriose, as well as colloidal chitin to yield chitobiose and is therefore considered an exochitinase. Chitotriosidase occurs in two major forms, the large form being converted to the small form by either RNA or post-translational processing. Although the small form, containing the chitinase domain alone, is sufficient for the chitinolytic activity, the additional C-terminal chitin-binding domain of the large form plays a role in processing colloidal chitin. The chitotriosidase gene is nonessential in humans, as about 35% of the population are heterozygous and 6% homozygous for an inactivated form of the gene. HCGP39 is a 39-kDa human cartilage glycoprotein thought to play a role in connective tissue remodeling and defense against pathogens.

Crystalstructure of Serratia marcescens Chitinase B complexed with compound 2-8-14 [Serratia marcescens],6JK9_B Crystal structure of Serratia marcescens Chitinase B complexed with compound 2-8-14 [Serratia marcescens],7C34_A Crystal structure of Serratia marcescens Chitinase B complexed with Berberine [Serratia marcescens],7C34_B Crystal structure of Serratia marcescens Chitinase B complexed with Berberine [Serratia marcescens]

Chitinaseb from Serratia marcescens mutant D142N [Serratia marcescens],1OGB_B Chitinase b from Serratia marcescens mutant D142N [Serratia marcescens],1OGG_A chitinase b from serratia marcescens mutant d142n in complex with inhibitor allosamidin [Serratia marcescens],1OGG_B chitinase b from serratia marcescens mutant d142n in complex with inhibitor allosamidin [Serratia marcescens]

Interactionsof a family 18 chitinase with the designed inhibitor HM508, and its degradation product, chitobiono-delta-lactone [Serratia marcescens],1UR9_B Interactions of a family 18 chitinase with the designed inhibitor HM508, and its degradation product, chitobiono-delta-lactone [Serratia marcescens]

Serratiamarcescens Chitinase B, tetragonal form [Serratia marcescens],3WD1_A Serratia marcescens Chitinase B complexed with syn-triazole inhibitor [Serratia marcescens],3WD2_A Serratia marcescens Chitinase B complexed with azide inhibitor [Serratia marcescens],3WD3_A Serratia marcescens Chitinase B complexed with azide inhibitor [Serratia marcescens],3WD4_A Serratia marcescens Chitinase B complexed with azide inhibitor and quinoline compound [Serratia marcescens],4Z2G_A Serratia marcescens Chitinase B complexed with macrolide inhibitor 26 [Serratia marcescens],4Z2H_A Serratia marcescens Chitinase B complexed with macrolide inhibitor 29 [Serratia marcescens],4Z2I_A Serratia marcescens Chitinase B complexed with macrolide inhibitor 30 [Serratia marcescens],4Z2J_A Serratia marcescens Chitinase B complexed with macrolide inhibitor 31 [Serratia marcescens],4Z2K_A Serratia marcescens Chitinase B complexed with macrolide inhibitor 32 [Serratia marcescens],4Z2L_A Serratia marcescens Chitinase B complexed with macrolide inhibitor 33 [Serratia marcescens]

ChainA, Chitinase [Serratia marcescens],7C92_B Chain B, Chitinase [Serratia marcescens]

Chitinase B OS=Serratia marcescens OX=615 GN=chiB PE=1 SV=1

Chitinase A1 OS=Niallia circulans OX=1397 GN=chiA1 PE=1 SV=1

Endochitinase B OS=Emericella nidulans OX=162425 GN=chiB PE=1 SV=3

Endochitinase B OS=Emericella nidulans (strain FGSC A4 / ATCC 38163 / CBS 112.46 / NRRL 194 / M139) OX=227321 GN=chiB PE=1 SV=1

Endochitinase 46 OS=Trichoderma harzianum OX=5544 GN=chit46 PE=1 SV=1