The chitobiose (chb) operon is involved in the synthesis of chitooligosaccharide and is comprised of a BCARFG gene cluster. ChbG encodes a chitooligosaccharide deacetylase (CDA) which catalyzes the removal of one acetyl group from N,N’-diacetylchitobiose. It is considered a novel type of CDA due to its lack of sequence homology. Although there are various structural studies of CDAs linked to the kinetic properties of the enzyme, the structural information of ChbG is unavailable. In this study, the crystal structure of ChbG from Klebsiella pneumoniae is provided. The molecular basis of deacetylation of diacetylchitobiose by ChbG is determined based on structural analysis, mutagenesis, biophysical analysis, and in silico docking of the substrate, diacetylchitobiose. This study contributes towards a deeper understanding of chitin and chitosan biology, as well as provides a platform to engineer CDA biocatalysts.

壳二糖( chb ) 操纵子参与壳寡糖的合成，由BCARFG基因簇组成。ChbG 编码壳寡糖脱乙酰酶 (CDA)，其催化从 N,N'-二乙酰壳二糖中去除一个乙酰基。由于缺乏序列同源性，它被认为是一种新型的CDA。尽管有各种与酶动力学特性相关的 CDA 结构研究，但无法获得 ChbG 的结构信息。在这项研究中，来自肺炎克雷伯菌的 ChbG 的晶体结构提供。ChbG 对二乙酰壳二糖脱乙酰化的分子基础是基于结构分析、诱变、生物物理分析和底物二乙酰壳二糖的计算机对接确定的。该研究有助于更深入地了解甲壳素和壳聚糖生物学，并为设计 CDA 生物催化剂提供平台。