CBD, Chitin binding domain

CAT-REL, vesicular catecholamine release CB-R, cannabinoid receptor CB1-R, CB2-R, cannabinoid receptors CBD, chitin-binding domain CBG, cortisol-binding globulin CBZ-R, central benzodiazepine receptor CCK-R, cholecystokinin receptor CDC, chrysanthemum dicarboxylic acid CDK, cell division kinase, cyclin-dependent protein kinase... 

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... 

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.

A full-length human csk DNA that codes for Csk, a 50-kDa protein that catalyzes the phosphorylation of a tyrosine within the C-terminal tail of Srk, was inserted in a plasmid and in-frame with a modified intein-chitin binding domain (CBD) encoding sequence, where intein is a protein-splicing element. 130 The expressed protein underwent a conversion into a thioester of the N-terminal cysteine of the intein, but the normal second step of an intein splicing did not occur. The protein was then bound to a chitin resin and washed. The resin containing the bound protein was treated with 2% benzenethiol to cleave the thioester and give the free phenyl thioester, which was immediately treated with one of the synthetic... 

Chen et al. (2008) have expressed a codon-optimized form of the CM4 peptide in E. coli. In this case, two alternative expression/purification systems were examined namely the widely used glutathione-S-transferase (GST) and a chitin-binding domain (CBD) system with associated intein splicing (New England Biolabs Inc.). The GST system failed to allow recovery of expressed fusion protein. In contrast, the CBD/intein system allowed the recovery of 110 mg/L fusion protein with a final RP-HPLC purification step yielding 2.1 mg/L of pure peptide which displayed antimicrobial activity against E. coli Ki2D3i and Salmonella. 

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... 

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