Enzymatic Analysis of Chitin Deacetylases on Crystalline Chitin with Varied Molecular Weights: Insights from Active Pocket Characteristic Analysis

Abstract

Chitin deacetylases (CDAs), which catalyze the deacetylation of chitin to produce chitosan, have garnered significant interest due to their environmental compatibility and ability to control product quality. However, the low conversion efficiency resulting from chitin’s high molecular weight and crystallinity, as well as structural limitations of CDAs, has impeded their industrial application. In this study, we present the integrated approach combining bioinformatics and computational tools (adaptive Poisson–Boltzmann solver, Fpocket, and ProteinPlus) to systematically analyze sequence features and variations in active pocket properties among CDAs from diverse origins. Experimental evaluation of the deacetylation activity of AnCDA, AsCDA, BaCDA, and ScCDA, each with distinct pocket characteristics, on chitin substrates with varying molecular parameters revealed that CDAs with high hydrophobicity scores and low surface-to-volume ratios exhibited superior efficiency in converting high-molecular-weight chitin. These findings guide the rational selection and engineering of CDAs for industrial biocatalysis.