Chitinase domain

Urtica CBP (chitinase-like Urtica dioica (stinging nettle) Chitin (but chitinase domain... 

The published filarial chitinases show a distinct modular domain structure (Fig. 10.3). The first 17-22 amino acids serve as a cleavable signal sequence, indicating that the enzymes are secreted or are components of the outer membrane. The catalytic domain, essential for the degradation of... 

Fig. 10.4. (Opposite) Alignments of nematode chitinases with the active centre boxed. Identical amino acids are marked with an asterisk ( ) similar amino acids are marked with a dot (.). Conserved cysteine residues in the chitin-binding domain are printed in bold. Gene Bank accession numbers C.eleg. Chit (C. elegans), Q11174 OvL3 Chit (O. volvulus), L42021 AvL3 Chit (A viteae), U14638 B.m. Chit(B. malayi), M73689.

Blaak, H., Schnellmann, J., Walter, S., Henrissat, B. and Schrempf, H. (1993) Characteristics of an exochitinase from Streptomyces olivaceoviridis, its corresponding gene, putative protein domains and relationship to other chitinases. European Journal of Biochemistry 214, 659-669. 

Malette, B., Paquette, Y., Merlen, Y. and Bleau, G. (1995) Oviductins possess chitinase and mucin-like domains a lead in the search for biological function of these oviduct-specific ZP-associating glycoproteins. Molecular Reproduction and Development 41, 384-397. 

Venegas, A., Goldstein, J.C., Beauregard, K, Oles, A., Abdulhayoglu, N. and Fuhrman, J.A. (1996) Expression of recombinant microfilarial chitinase and analysis of domain function. Molecular and, Biochemical Parasitology 78, 149-159. 

Shinshi, H., Neuhaus, J.M., Ryals, J. Meins, F. (1990). Structure of a tobacco endochitinase gene evidence that different chitinase genes can arise by transposition of sequences encoding a cysteine-rich domain. Plant Molecular Biology 14, 357-68. 

Plants also produce structurally related enzymes (chitinases) that catalyse the hydrolysis of chitin (Table 12.2) and hence damage chitin-based insect integuments. Class I chitinases are basic enzymes with an jV-terminal hevein-related CBD and vacuole-targeting C-terminal signals whereas Class II enzymes are acidic proteins lacking these CBD and vacuole-targeting domains. Class IV chitinases are variously basic and acidic extracellular proteins with... 

Sambucus CBP SN-HLPf (hevein-like N-terminal domain Class V chitinase-like C-terminal domain) Sambucus nigra (elderberry) (Caprifoliaceae) [fruit] Chitin... 

Other Non-Catalytic Domains. Many polysaccharide depolymerizing enzymes are secreted by bacteria and fungi from their intracellular site of synthesis across the periplasmic space and cell wall into the surroundings. These exported enzymes reach their destination via the general secretory pathway [246] which involves membrane protein complexes such as the bacterial ABC transporters [247] that recognize domains on the secreted proteins. There are several examples of non-catalytic domains on microbial carbohydrases that may play a role in transport from the cells. These include a repeat domain on a chitinase involved... 

Although the specificity of the CBMs binding polysaccharides is the same as the catalytic domain more often than not, there are many examples to the contrary from enzymes hydrolysing the plant cell wall. Thus, an acetylxylan esterase Cellvibrio japonicus ioxm.Qx y P.fluorescens subsp. cellulosa) contains a cellulose binding domain. Moreover the modular structure permits fairly complicated proteins to be built up one chitinase, for example, from a hyperthermophilic archeon, had two GH 18 catalytic domains and two Family 1 and a Family 5 CBMs. °... 

The same disposition of three planar hydrophobic aromatic residues is also adopted by CBM 5 and CBM 10, as other CBMs which have Type A function and unique protein folds. An NMR structure of the 60-residue CBM 5 of an Erwinia chrysanthemi endoglucanase revealed a ski-boot structure, with a flat hydrophobic face corresponding to the sole and heel of the ski-boot. This hydrophobic face contained the three planar hydrophobic residues (two tyrosines and a tryptophan).Also using a CBM 5, but as a chitin binding domain, is the chitinase B of Serratia marcescens (the catalytic domain being GH 18). ... 

C. Blanco, Latex-fruit syndrome, Curr. Allergy Asthma Rep., 3 (2003) 47-53 A. Diaz-Perales, C. Collada, C. Blanco, R. Sanchez-Monge, T. Carrillo, C. Aragoncillo, and G. Salcedo, Class I chitinases with hevein-like domain, but not class II enzymes, are relevant chestnut and avocado allergens, J. Allergy Clin. Immunol, 102 (1998) 127-133. 

Arakane Y, Zhu Q, Matsumiya M, Muthukrishnan S, Kramer KJ. Properties of catalytic, linker and chitin-binding domains of insect chitinase. Insea Biochem. Mol. Biol. 2003, 33, 631-648. 

Additional chitinase CBD proteins (chitin-binding domains) encoded by the amphioxus genome are of antimicrobial substances. The other urochordate Ciona intestinalis possesses three VCBP3-Uke genes (vide supra) and releases some 40 CBDs. In the Citidaria phylum (anemones, corals, jellyfish), Nematostella vectensis... 

The bacterium, Serratia marcescens, is one of the most extensively studied multiple chitinases producer (Horn et al. 2006 Suzuki et al. 2002 Vaaje-Kolstad et al. 2005). This bacterium possesses three chitinases ChiA, ChiB, and ChiC, as well as one chitin-binding protein CBP21. ChiC often occurs in two forms in cultures of this bacterium the complete protein, sometimes called ChiCl, and a proteolytically truncated variant, called ChiC2, which lacks the two putative chitin-binding domains. ChiC is suggested as an endo-chitinase and degrade chitin in a nonprogressive mode. 

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