National Glycoengineering Research Center and Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, 72 Binhai Rd, Qingdao 266200, China.
National Glycoengineering Research Center and Shandong Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, 72 Binhai Rd, Qingdao 266200, China; School of Life Science and Technology, Weifang Medical University, 7166 Baotong West Street, Weifang 261053, China.
Int J Biol Macromol. 2020 Dec 15;165(Pt B):2314-2325. doi: 10.1016/j.ijbiomac.2020.10.119. Epub 2020 Oct 22.
Chondroitin sulfate (CS)/dermatan sulfate (DS) lyases play important roles in structural and functional studies of CS/DS. In this study, a novel CS/DS lyase (enCSase) was identified from the genome of the marine bacterium Photobacterium sp. QA16. This enzyme is easily heterologously expressed and purified as highly active form against various CS, DS and hyaluronic acid (HA). Under the optimal conditions, the specific activities of this enzyme towards CSA, CSC, CSD, CSE, DS and HA were 373, 474, 171, 172, 141 and 97 U/mg of proteins, respectively. As an endolytic enzyme, enCSase degrades HA to unsaturated hexa- and tetrasaccharides but CS/DS to unsaturated tetra- and disaccharides as the final products. Sequencing analysis showed that the structures of tetrasaccharides in the final products of CS variants were not unique but were highly variable, indicating the randomness of substrate degradation by this enzyme. Further studies showed that the smallest substrate of enCSase was octasaccharide for HA but hexasaccharide for CS/DS, which could explain why this enzyme cannot degrade HA hexa- and tetrasaccharides and CS/DS tetrasaccharides further. It is believed that enCSase may be a very useful tool for structural and functional studies and related applications of CS/DS and HA.
硫酸软骨素（CS）/硫酸皮肤素（DS）裂解酶在 CS/DS 的结构和功能研究中起着重要作用。在本研究中，从海洋细菌 Photobacterium sp. QA16 的基因组中鉴定出一种新型 CS/DS 裂解酶（enCSase）。该酶易于异源表达和纯化，可高效作用于各种 CS、DS 和透明质酸（HA）。在最佳条件下，该酶对 CSA、CSC、CSD、CSE、DS 和 HA 的比活性分别为 373、474、171、172、141 和 97 U/mg 蛋白质。作为一种内裂解酶，enCSase 将 HA 降解为不饱和六糖和四糖，但 CS/DS 降解为不饱和四糖和二糖作为最终产物。测序分析表明，CS 变体最终产物中四糖的结构不是唯一的，而是高度可变的，表明该酶对底物降解的随机性。进一步的研究表明，enCSase 的最小底物是 HA 的八糖，CS/DS 的六糖，这可以解释为什么该酶不能进一步降解 HA 的六糖和四糖以及 CS/DS 的四糖。enCSase 可能是 CS/DS 和 HA 的结构和功能研究以及相关应用的非常有用的工具。
