Guo Yuxing, Li Xiangyue, Yang Yao, Wu Zhen, Zeng Xiaoqun, Nadari Fawze, Pan Daodong
Department of Food Science & Nutrition, Ginling College, Nanjing Normal University, Nanjing, 210097, People's Republic of China.
Key Laboratory of Animal Protein Deep Processing Technology of Zhejiang Province, Ningbo University, Ningbo, 315211, Zhejiang, People's Republic of China.
AMB Express. 2018 Jun 23;8(1):103. doi: 10.1186/s13568-018-0631-2.
The slpB gene of Lactobacillus acidophilus NCFM, which differs from the slpA gene and is silent under normal conditions, was successfully amplified and ligated to the corresponding available sites on a recombinant pET-28a vector. Then the pET-28a-slpB vector was transformed into Escherichia coli DH (DE3) and the fusion His-slpB protein was expressed by induction with 1 mM IPTG for 14 h at 37 °C. The resulting His-slpB protein (S) had a relative molecular weight of 48 kDa. It was purified using a Ni-NTA column and was confirmed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blot contrastive analysis. The slpA protein (S) from L. acidophilus NCFM was extracted and purified. It had a relative molecular weight of 46 kDa. Circular dichroism measurements suggested that the two S-layer proteins had a high β-sheet content and a low α-helix structure content. In an adhesion experiment, S displayed higher adhesive capability towards Caco-2 cells than did S. The results suggest that these two S-layer proteins could have biotechnological applications.
嗜酸乳杆菌NCFM的slpB基因与slpA基因不同，在正常条件下不表达，该基因被成功扩增并连接到重组pET-28a载体的相应可用位点上。然后将pET-28a-slpB载体转化到大肠杆菌DH(DE3)中，通过在37℃下用1 mM IPTG诱导14小时来表达融合His-slpB蛋白。所得的His-slpB蛋白(S)的相对分子质量为48 kDa。使用镍-亚氨基二乙酸(Ni-NTA)柱对其进行纯化，并通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳和蛋白质免疫印迹对比分析进行确认。提取并纯化了嗜酸乳杆菌NCFM的slpA蛋白(S)。其相对分子质量为46 kDa。圆二色性测量表明，这两种S层蛋白具有较高的β-折叠含量和较低的α-螺旋结构含量。在黏附实验中，S对Caco-2细胞的黏附能力高于S。结果表明，这两种S层蛋白可能具有生物技术应用价值。
