Prokaryotic expression and purification of SARS-CoV-2 N protein

ABSTRACT

Bioinformatics methods were used to predict the hydrophilicity, hydrophobicity, antigen epitopes and analyse multiple sequence alignment of the nucleocapsid protein (N protein) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The recombinant plasmid pET28a/ N was constructed. In the prokaryotic expression system of Escherichia coli, the solubility and expression level of the protein were improved by adjusting the change of induction temperature and time, and the expressed recombinant N protein was purified and identified. The results showed that SARS-CoV-2 N encoded 419 amino acids, with an isoelectric point (PI) of 10.10, no transmembrane region, no signal peptide sequence, and strong local hydrophilicity. The full-length protein had a high antigenic index and was highly conserved, and its homology with SARS-CoV N protein was 90.5%. After fermentation with Escherichia coli prokaryotic expression system, the engineering strain BL21 (DE3)/pET28a/N was induced at 16 °C for 20 h with the final IPTG concentration of 0.2 mmol/L, and the protein was soluble and most pressed at this time, accounting for 70% of the total protein expression. The target protein purified by Ni-NTA affinity chromatography and gel filtration chromatography had a purity of 90% and a molecular weight of 55 kDa, which was specific. [ FROM AUTHOR] Copyright of Journal of Light Industry is the property of Journal of Zhengzhou University of Light Industry, Natural Science Edition and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full . (Copyright applies to all s.)