Department of Biotechnology and Bioinformatics, Korea University, 2511 Sejong-Ro, Sejong, 30019, South Korea.
Appl Microbiol Biotechnol. 2019 Mar;103(5):2205-2216. doi: 10.1007/s00253-018-09595-w. Epub 2019 Jan 4.
The Escherichia coli (E. coli) expression system has been widely used to produce recombinant proteins. However, in some heterologous expressions, there are still difficulties in large-scale production. The use of fusion partners is one of the strategies for improving the expression levels of proteins in E. coli host. Here, we demonstrate a novel fusion element, the NT11-tag, which enhances protein expression. The NT11-tag was derived from the first 11 amino acid residues within the N-terminal N-half domain of a duplicated carbonic anhydrase (dCA) from Dunaliella species. Previously, we have found that the tag improves expression of the C-half domain of dCA when linked to its N-terminus. To verify its use as a protein production enhancer tag, two kinds of CAs derived from Hahella chejuensis (Hc-CA) and Thermovibrio ammonifican (Ta-CA) and the yellow fluorescent protein (YFP) were used as model proteins to measure their increased expression upon fusion with the NT11-tag. The NT11-tag amplified protein expression in E. coli by 6.9- and 7.6-fold for Ta-CA and YFP, respectively. Moreover, the tag also enhanced the soluble expression of Hc-CA, Ta-CA, and YFP by 1.7-, 5.0-, and 3.2-fold, respectively. Furthermore, protein yield was increased without inhibiting protein function. These results indicate that the use of the NT11-tag is a promising method for improving protein production in E. coli.
大肠杆菌（E. coli）表达系统已广泛用于生产重组蛋白。然而，在某些异源表达中，大规模生产仍存在困难。使用融合伴侣是提高大肠杆菌宿主中蛋白质表达水平的策略之一。在这里，我们展示了一种新的融合元件，NT11 标签，它可以增强蛋白质的表达。NT11 标签源自杜氏盐藻（Dunaliella）种的重复碳酸酐酶（dCA）的 N 端 N-半结构域的前 11 个氨基酸残基。以前，我们发现该标签与 dCA 的 C 端相连时，可以提高其表达。为了验证其作为蛋白质生产增强标签的用途，我们使用两种源自海豆芽（Hahella chejuensis）的碳酸酐酶（Hc-CA）和氨化球菌（Thermovibrio ammonifican）（Ta-CA）以及黄色荧光蛋白（YFP）作为模型蛋白，来衡量它们与 NT11 标签融合后表达的增加。NT11 标签分别使 Ta-CA 和 YFP 的蛋白表达量增加了 6.9 倍和 7.6 倍。此外，该标签还分别将 Hc-CA、Ta-CA 和 YFP 的可溶性表达提高了 1.7 倍、5.0 倍和 3.2 倍。此外，蛋白产量的增加不会抑制蛋白功能。这些结果表明，使用 NT11 标签是提高大肠杆菌中蛋白质生产的一种很有前途的方法。
