Jiangsu Key Laboratory of Marine Bioresources and Environment/Jiangsu Key Laboratory of Marine Biotechnology, Jiangsu Ocean University, 59 Cangwu Road, Lianyungang 222005, PR China.
Co-Innovation Center of Jiangsu Marine Bio-industry Technology, Jiangsu Ocean University, 59 Cangwu Road, Lianyungang 222005, PR China.
FEMS Microbiol Lett. 2021 Feb 12;368(3). doi: 10.1093/femsle/fnab007.
Dextranase specifically hydrolyzes dextran and is used to produce functional isomalto-saccharide prebiotics. Moreover, dextranase is used as an additive in mouthwash to remove dental plaque. We cloned and expressed the dextranase gene of the marine bacterium Bacillus aquimaris S5. The length of the BaDex gene was 1788 bp, encoding 573 amino acids. Using bioinformatics to predict and analyze the amino acid sequence of BaDex, we found the isoelectric point and instability coefficient to be 4.55 and 29.22, respectively. The average hydrophilicity (GRAVY) was -0.662. The secondary structure of BaDex consisted of 145 alpha helices, accounting for 25.31% of the protein; 126 extended strands, accounting for 21.99%; and 282 random coils, accounting for 49.21%. The 3D structure of the BaDex protein was predicted and simulated using SWISS-MODEL, and BaDex was classified as a Glycoside Hydrolase Family 66 protein. The optimal temperature and pH for BaDex activity were 40°C and 6.0, respectively. The hydrolysates had excellent antioxidant activity, and 8 U/mL of BaDex could remove 80% of dental plaque in MBRC experiment. This recombinant protein thus has great promise for applications in the food and pharmaceutical industries.
葡聚糖酶特异性水解葡聚糖，用于生产功能性异麦芽低聚糖益生元。此外，葡聚糖酶还可用作漱口水的添加剂，以去除牙菌斑。我们克隆并表达了海洋细菌Aquimaribacterium aquimaris S5 的葡聚糖酶基因。BaDex 基因的长度为 1788bp，编码 573 个氨基酸。通过生物信息学预测和分析 BaDex 的氨基酸序列，我们发现其等电点和不稳定性系数分别为 4.55 和 29.22。平均亲水性（GRAVY）为-0.662。BaDex 的二级结构由 145 个α螺旋组成，占蛋白质的 25.31%；126 个伸展链，占 21.99%；282 个无规则卷曲，占 49.21%。使用 SWISS-MODEL 预测和模拟了 BaDex 蛋白的 3D 结构，BaDex 被归类为糖苷水解酶家族 66 蛋白。BaDex 活性的最佳温度和 pH 值分别为 40°C 和 6.0。水解产物具有优异的抗氧化活性，8U/mL 的 BaDex 可在 MBRC 实验中去除 80%的牙菌斑。因此，这种重组蛋白在食品和制药行业具有广阔的应用前景。
