Production of SARS-CoV-2 Spike Protein Model

In our previous work, the nucleocapsid (N) protein of SARS-CoV-2 was focused on synthesizing the Model-N by phage display. Similarly, in this study, the spike (S) protein was targeted and used to produce the Model-S following the same protocol. The S protein of SARS-CoV-2 has a molecular weight of about 180–200 kDa. Figure 6 illustrates the processing for the synthesis of Model-S.
After searching the gene corresponding to the S protein of SARS-CoV-2 at the National Center for Biotechnology Information (NCBI) website (Gene ID: 43740568), it was modified by adding SfiI and NotI restriction digest sites on both sides. After the regular PCR amplification and double endonuclease digestion by SfiI/NotI enzyme, the inserted fragment was prepared. The dosage and duration conditions were in accordance with the previous work, as shown in Table 8 (a) and (b) [45 (link)].
When the vector pHB was digested by the same enzymes as well, the two parts were constructed and combined with recombinant vector pHB-S produced. The experimental conditions followed the same protocol preparing pHB-N, as presented in Table 9 [45 (link)].
Then, it was transformed into the competent E. coli TG1. After cultivation, M13 phages were added to infect TG1, and the synthesized Model-S was finally produced after filtrations. The specific cultivation process was described before [45 (link)].