从链霉菌属 sampsonii 中分离得到的一种具有几丁质酶/溶菌酶双重活性的酶的生化特性研究，该酶适合用于 N-乙酰壳二糖的生产。
Biochemical characterization of a bifunctional chitinase/lysozyme from Streptomyces sampsonii suitable for N-acetyl chitobiose production.
机构信息
Key Laboratory of Food Bioengineering (China National Light Industry), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China.
Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Engineering, China Agricultural University, Beijing, 100083, China.
出版信息
Biotechnol Lett. 2020 Aug;42(8):1489-1499. doi: 10.1007/s10529-020-02834-z. Epub 2020 Mar 13.
OBJECTIVES
Chitinases play important role in chitin bioconversion, while few of them have been put into use due to their poor properties. We aimed to identify and characterize chitinases suitable for N-acetyl chitooligosaccharides (COSs) production from chitin materials.
RESULTS
A chitinase gene (SsChi28) from Streptomyces sampsonii XY2-7 was cloned and heterologously expressed in E. coli BL21 (DE3) as an active protein. The deduced protein shared high sequence identities and structure similarities with some glycoside hydrolase family 19 chitinases. The recombinant enzyme (SsChi28) was purified and biochemically characterized. SsChi28 was a monomeric protein with a molecular mass of 30 kDa estimated by SDS-PAGE. It was most active at pH 6.0 and 55 °C, respectively, and stable in a wide pH range of 3.5-11.5 and up to 60 °C. The enzyme exhibited strict substrate specificities towards ethylene glycol chitin (222.3 U/mg) and colloidal chitin (20.1 U/mg). Besides, it displayed lysozyme activity against Micrococcus lysodeikticus. SsChi28 hydrolyzed colloidal chitin to yield mainly N-acetyl chitobiose, accounting high up to 73% (w/w) in total products.
CONCLUSION
The excellent enzymatic properties of SsChi28 may make it potential in chitin bioconversion (especially for N-acetyl COS production), as well as in biological control of fungal diseases.
目的
几丁质酶在几丁质生物转化中发挥着重要作用，但由于其性质较差，很少被应用。我们旨在鉴定和表征适合从几丁质材料生产 N-乙酰壳寡糖（COSs）的几丁质酶。
结果
从链霉菌 XY2-7 中克隆并在大肠杆菌 BL21（DE3）中异源表达了一种几丁质酶基因（SsChi28），表达的蛋白为活性蛋白。该推导蛋白与一些糖苷水解酶家族 19 几丁质酶具有很高的序列同一性和结构相似性。重组酶（SsChi28）被纯化并进行了生化特性分析。SsChi28 是一种单体蛋白，通过 SDS-PAGE 估计其分子量为 30 kDa。它在 pH 6.0 和 55°C 时最活跃，在 pH 3.5-11.5 的较宽范围内稳定，最高可达 60°C。该酶对乙二醇壳聚糖（222.3 U/mg）和胶体壳聚糖（20.1 U/mg）具有严格的底物特异性。此外，它对溶壁微球菌具有溶菌酶活性。SsChi28 水解胶体壳聚糖主要产生 N-乙酰壳二糖，总产物中高达 73%（w/w）。
结论
SsChi28 的优异酶学特性使其可能适用于几丁质生物转化（特别是 N-乙酰 COS 生产），以及真菌病害的生物防治。
Zotero 插件