Wang, L.; Fei, M.; Zhang, W.; Lin, S.; Jiang, Z.; Zhang, S.; Wang, Y.

Rapid production of soluble recombinant antigens is important for developing in vitro diagnostics, vaccines, and drugs against virus such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In this research, hard-to-express nucleocapsid, membrane, and envelope proteins were successfully expressed by an Escherichia coli-based cell-free protein synthesis system. The solubility of the proteins was optimized using various amphipathic molecules. Most of the impurities were easily removed by a one-step Ni-NTA affinity chromatography. This study provides an easy and quick alternative for virus trans-membrane and nucleotides associated recombinant protein expression, which has potential downstream application for early screening of newly emerging viruses.