Jiang Zedong, Guo Yuxi, Wang Xinxia, Li Hebin, Ni Hui, Li Lijun, Xiao Anfeng, Zhu Yanbing
College of Food and Biological Engineering, Jimei University, Xiamen, 361021, China; Fujian Provincial Key Laboratory of Food Microbiology and Enzyme Engineering, Xiamen, 361021, China; Research Center of Food Biotechnology of Xiamen City, Xiamen, 361021, China; Key Laboratory of Systemic Utilization and In-depth Processing of Economic Seaweed, Xiamen Southern Ocean Technology Center of China, Xiamen, 361021, China.
College of Food and Biological Engineering, Jimei University, Xiamen, 361021, China.
Protein Expr Purif. 2019 Sep;161:17-27. doi: 10.1016/j.pep.2019.03.015. Epub 2019 Mar 27.
A new alginate lyase gene of algl17 was cloned from an alginate-degrading marine bacterium Microbulbifer sp. ALW1. The gene contained 2220 bp and encoded a 739-amino acid protein classified into the PL-17 family. The recombinant alginate lyase AlgL17 was overexpressed and purified from Escherichia coli BL21 (DE3) with a molecular mass of 84.9 kDa. This enzyme showed activities towards sodium alginate, polyM and alginate oligosaccharide, but very low activity towards polyG. These results indicate that AlgL17 is a polyM-specific oligoalginate lyase. When sodium alginate was used as a substrate, the optimum reaction temperature and pH for the enzyme were 35 °C and pH 8.0, respectively. Recombinant AlgL17 was stable at 25 °C, but not stable at 30 °C and 35 °C. It showed good stability over a pH range of 5.0-8.0. The enzyme activity was increased to 1.7 times by adding NaCl to a final concentration of 0.7 M. The ability of the recombinant AlgL17 producing 4-deoxy-L-erythro-5-hexoseulose uronic acid (DEH) from sodium alginate and polyM block indicates that AlgL17 is an exo-type alginate lyase.
从一株降解海藻酸盐的海洋细菌微小杆菌属ALW1中克隆出一个新的海藻酸盐裂解酶基因algl17。该基因包含2220 bp，编码一个739个氨基酸的蛋白质，属于PL-17家族。重组海藻酸盐裂解酶AlgL17在大肠杆菌BL21(DE3)中过量表达并纯化，分子量为84.9 kDa。该酶对海藻酸钠、聚甘露糖醛酸（polyM）和海藻寡糖有活性，但对聚古罗糖醛酸（polyG）活性很低。这些结果表明AlgL17是一种聚甘露糖醛酸特异性的寡聚海藻酸盐裂解酶。以海藻酸钠为底物时，该酶的最适反应温度和pH分别为35℃和pH 8.0。重组AlgL17在25℃下稳定，但在30℃和35℃下不稳定。它在pH 5.0-8.0范围内表现出良好的稳定性。通过添加终浓度为0.7 M的NaCl，酶活性提高到1.7倍。重组AlgL17从海藻酸钠和聚甘露糖醛酸产生4-脱氧-L-赤藓糖-5-己糖醛酸（DEH）的能力表明AlgL17是一种外切型海藻酸盐裂解酶。
