Key Laboratory of Food Bioengineering (China National Light Industry), College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, China.
College of Engineering, China Agricultural University, Beijing 100083, China.
Int J Biol Macromol. 2021 Jul 1;182:1528-1536. doi: 10.1016/j.ijbiomac.2021.05.111. Epub 2021 May 19.
A chitinase gene (PxChi52) from Paenibacillus xylanexedens Z2-4 was cloned and heterologously expressed in Escherichia coli BL21 (DE3). PxChi52 shared the highest identity of 91% with a glycoside hydrolase family 18 chitinase (ChiD) from Bacillus circulans. The recombinant enzyme (PxChi52) was purified and biochemically characterized. PxChi52 had a molecular mass of 52.8 kDa. It was most active at pH 4.5 and 65 °C, respectively, and stable in a wide pH range of 4.0-13.0 and up to 50 °C. The enzyme exhibited the highest specific activity of 16.0 U/mg towards colloidal chitin, followed by ethylene glycol chitin (5.4 U/mg) and ball milled chitin (0.4 U/mg). The K and V values of PxChi52 towards colloidal chitin were determined to be 3.06 mg/mL and 71.38 U/mg, respectively, PxChi52 hydrolyzed colloidal chitin and chitooligosaccharides with degree of polymerization 2-5 to release mainly N-acetyl chitobiose. In addition, PxChi52 displayed inhibition effects on the growth of some phytopathogenic fungi, including Alternaria alstroemeriae, Botrytis cinerea, Rhizoctonia solani, Sclerotinia sclerotiorum and Valsa mali. The unique properties of PxChi52 may enable it potential application in agriculture field as a biocontrol agent.
从解淀粉芽孢杆菌 Z2-4 中克隆并异源表达了一种几丁质酶基因（PxChi52）。PxChi52 与环状芽孢杆菌的糖苷水解酶家族 18 几丁质酶（ChiD）的同源性最高，为 91%。重组酶（PxChi52）被纯化并进行了生化特性分析。PxChi52 的分子量为 52.8 kDa。它在 pH4.5 和 65°C 时活性最高，在 pH4.0-13.0 的宽范围内稳定，最高可达 50°C。该酶对胶体几丁质的比活力最高，为 16.0 U/mg，其次是乙二醇几丁质（5.4 U/mg）和球磨几丁质（0.4 U/mg）。PxChi52 对胶体几丁质的 K 和 V 值分别为 3.06 mg/mL 和 71.38 U/mg。PxChi52 水解胶体几丁质和聚合度为 2-5 的几丁寡糖，主要释放 N-乙酰壳二糖。此外，PxChi52 对几种植物病原菌真菌的生长具有抑制作用，包括葱链格孢菌、灰葡萄孢菌、立枯丝核菌、核盘菌和苹果腐烂病菌。PxChi52 的独特性质使其可能作为一种生物防治剂在农业领域具有潜在的应用价值。
