Binding chitin

Rebers J. E. and WUlis J. H. 2001. A conserved domain in arthropod cuticular proteins binds chitin. Insect Biochem Mol Biol 31 1083-1093. 

After this, we demonstrated the ability of wheat anionic POs to bind to the chitin of the cell walls of fungal pathogens. We called these POs "chitin-binding POs" (Maksimov et al., 2003). We were the first to demonstrate the binding of the anionic PO of wheat root to chitin (Maksimov et al., 1994). Besides this, we observed that in some species the activity of POs was increased in the unbound Armoracia rustkana, Lagenaria siceraria) or eluted Pisum sativum, Galega orientalis, Brassica oleraceae) fractions of proteins after interaction with chitin. 

Crude extract Unbound with chitin fraction Binding with chitin fraction ... 

Fig. 3. The scheme of the precipitates formed by the crude protein extracts of plants of the groups monocotyledons (1-11, table 1) and dicotyledons (12-23 table 1) with antibodies against wheat chitin-binding proteins (I) and with antibodies against wheat anionic PO (H).

Akhunov et al. (2008) purified chitin-specific PO with fungicidal activity from cotton and observed the increase of its activity in plants, penetrated by Verticillium dahliae. Golubenco et al. (2007) showed the presence of the chitin-binding PO isozyme in Hibiscus trionum, which activated dramatically after inoculation by V, dahliae. The plants of Nicotiana tabacum overexpressing the anionic PO (chitin-specific according to our data) were more resistant to Helicoverpa zea and Lasioderma serricorne as compared with the wild-type (Dowd et al., 2006). 

Therefore, the ability of certain POs to bind with chitin is a widespread phenomenon and -possibly - connected with the defence reactions of the organisms to pathogen attacks. Since it was shown that some biogenic molecules - such as chitooligosaccharides or salicylic acid -can activate an anionic POs, we might suggest that an application of these compounds optimises the process of anionic PO isolation with a chitin. 

The ability of PO to interact with the acetyl residues of chitin allows us to compare them with monovalent lectins (i.e. extensins) which when binding with hemicellulose are only affected in a medium with a high ionic strength (Brownleader et al., 2006). As a rule, POs are bound with the plant cell wall and act as its modifiers. Some POs can form complexes with an extensin of cell walls (Brownleader et al., 2006). Consequently, chitin-specific sites that are capable of interacting with polysaccharides exist in the molecules of PO, and these sites can resemble the membrane receptor binding sites or else be similar to the domains of heparinbinding proteins (Kim et al., 2001). 

Fig. 18 CG15920 gene sequence and primary structure. The consensus repeat sequences are also represented. The highlighted regions correspond to the signal sequence, R R chitin-binding domain, and the elastomeric domains containing repeat motifs A and B. Reproduced from [182, 188] with permission from Elsevier, copyright Elsevier 2001, 2010...

Fig. 21 Chitin binding of 6xHis-tagged resilin with chitin-binding domain (6 H-resChBD) as compared to 6xHis-tagged resilin without chitin-binding domain (6 H-res). T total protein after affinity chromatography purification, B bound protein eluted from chitin beads, UB unbound protein. Reproduced from [187] with permission from The American Chemical Society, copyright 2009...

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.

Renkema, G.H., Boot, R.G., Au, F.L., Donker-Koopman, W.E., Strijland, A., Muijsers, A.O., Hrebicek, M. and Aerts, J.M. (1998) Chitotriosidase, a chitinase, and the 39-kDa human cartilage glycoprotein, a chitin-binding lectin, are homologues of family 18 glycosyl hydrolases secreted by human macrophages. European Journal of Biochemistry 251, 504-509. 

Poly(HASCL) depolymerases are able to bind to poly(3HB)-granules. This ability is specific because poly(3HB) depolymerases do not bind to chitin or to (crystalline) cellulose [56,57]. The poly(3HB)-binding ability is lost in truncated proteins which lack the C-terminal domain of about 60 amino acids, and these modified enzymes do not hydrolyze poly(3HB). However, the catalytic domain is unaffected since the activity with water-soluble oligomers of 3-hy-droxybutyrate or with artificial water-soluble substrates such as p-nitrophenyl-esters is unaffected [55, 56, 58, 59]. Obviously, the C-terminal domain of poly(3HB) depolymerases is responsible and sufficient for poly(3HB)-binding [poly(3HB)-binding domain]. These results are in agreement ... 

Fusion vectors are available that combine a recombinant protein with a mutant mini intein segment (not containing an endonuclease domain) and followed by a chitin binding domain (CBD Zhang et al., 2001). These mutants typically also have an alanine substitution that replaces the cysteine or serine/threonine usually found on the C-extein splice junction. Alanine... 

Figure 19.7 Molecular correspondence of the inorganic-organic interface in the nacreous shell layer of Nautilus repertus. (a) Structural relationships between protein sheets, aragonite crystals and chitin fibres, (b) Possible complementarity of Ca binding. (From Mann et al., 1989. Reproduced with permission from John Wiley Sons., Inc.)...

Fig. 1.4 A I ntein-mediated protein ligation (IPL) (also called expressed protein ligation EPL). B The chemical mechanism of protein cyclization by the IPL/EPL approach. HAC denotes the sequence of the active site of the intein, e.g. His-Ala-Cys. CBD stands for chitin-binding domain.

Fig. 1.6 A IPL/EPL cyclization with the IMPACT system, B backbone cyclization using the TWIN inteins. CBD stands for chitin-binding domain. N-termini are indicated by NH2.

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