Abstract: In order to optimize the construction of prokaryotic expression vector of SARS-CoV-2 nucleocapsid protein and obtain the re-combinant fusion protein expressed inEscherichiacoli, we first analyzed the sequential similarities between SARS-CoV-2 nucleocapsidprotein and other β-CoV nucleocapsid proteins, as well as the secondary and tertiary structures using public genomic data and proteinprediction tools. Then, a recombinant vector pET-N with His tag was constructed and transformed into BL21 cells. The target protein was next induced and expressed by IPTG. Finally, the recombinant fusion protein was purified by affinity chromatography and identi-fied by both SDS-PAGE and Western Blot. We found that the recombinant fusion protein existed in both the supernatant and the inclu-sion body, as well the target protein was purified by breaking the inclusion body. The recombinant fusion protein provides an alternativeway of detecting the antibody in the serum of infected persons at the full advantages of the bioinformatics methodology.

Key words: coronavirus, nucleocapsid protein, SARS-CoV-2, prokaryotic expression, indirect ELISA