Catalytic NodB homology domain of Mucor rouxii chitin deacetylase and similar proteins
This family is represented by the chitin deacetylase (MrCDA, EC 3.5.1.41) encoded from the fungus Mucor rouxii (also known as Amylomyces rouxii). MrCDA is an acidic glycoprotein with a very stringent specificity for beta1-4-linked N-acetylglucosamine homopolymers. It requires at least four residues (chitotetraose) for catalysis, and can achieve extensive deacetylation on chitin polymers. MrCDA shows high sequence similarity to Colletotrichum lindemuthianum chitin deacetylase (endo-chitin de-N-acetylase, ClCDA), which consists of a single catalytic domain similar to the deformed (beta/alpha)8 barrel fold adopted by the carbohydrate esterase 4 (CE4) superfamily, which encompasses a mononuclear metalloenzyme employing a conserved His-His-Asp zinc-binding triad closely associated with the conserved catalytic base (aspartic acid) and acid (histidine) to carry out acid/base catalysis. The family also includes some uncharacterized eukaryotic and bacterial homologs of MrCDA.
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