Department of Integrative Biotechnology, College of Biotechnology and Bioengineering, Sungkyunkwan University, Suwon, Gyeonggi, 16419, Republic of Korea; Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
Metab Eng. 2021 Sep;67:277-284. doi: 10.1016/j.ymben.2021.07.007. Epub 2021 Jul 16.
Escherichia coli-based whole-cell biocatalysts are widely used for the sustainable production of value-added chemicals. However, weak acids present as substrates and/or products obstruct the growth and fermentation capability of E. coli. Here, we show that a viroporin consisting of the influenza A matrix-2 (M2) protein, is activated by low pH and has proton channel activity in E. coli. The heterologous expression of the M2 protein in E. coli resulted in a significant increase in the intracellular pH and cell viability in the presence of various weak acids with different lengths of carbon chains. In addition, the feasibility of developing a robust and efficient E. coli-based whole-cell biocatalyst via introduction of the proton-selective viroporin was explored by employing (Z)-11-(heptanolyoxy)undec-9-enoic acid (ester) and 2-fucosyllactose (2'-FL) as model products, whose production is hampered by cytosolic acidification. The engineered E. coli strains containing the proton-selective viroporin exhibited approximately 80% and 230% higher concentrations of the ester and 2'-FL, respectively, than the control strains without the M2 protein. The simple and powerful strategy developed in this study can be applied to produce other valuable chemicals whose production involves substrates and/or products that cause cytosolic acidification.
基于大肠杆菌的全细胞生物催化剂被广泛用于可持续生产增值化学品。然而，作为底物和/或产物的弱酸会阻碍大肠杆菌的生长和发酵能力。在这里，我们展示了一种由流感 A 基质-2 (M2) 蛋白组成的病毒孔蛋白，它在低 pH 值下被激活，并在大肠杆菌中具有质子通道活性。M2 蛋白的异源表达导致在存在各种具有不同碳链长度的弱酸时，细胞内 pH 值和细胞活力显著增加。此外，通过引入质子选择性病毒孔蛋白，探索了开发稳健高效的基于大肠杆菌的全细胞生物催化剂的可行性，使用 (Z)-11-(庚醇氧基)十一-9-烯酸（酯）和 2-岩藻糖基乳糖（2'-FL）作为模型产物，其生产受到细胞质酸化的阻碍。含有质子选择性病毒孔蛋白的工程大肠杆菌菌株的酯和 2'-FL 浓度分别比没有 M2 蛋白的对照菌株高约 80%和 230%。本研究中开发的简单而强大的策略可用于生产其他有价值的化学品，其生产涉及导致细胞质酸化的底物和/或产物。
