Abstract
The continuous mutation of SARS-CoV-2 has presented enormous challenges to global pandemic prevention and control. Recent studies have shown evidence that the genome sequence of SARS-CoV-2 nucleocapsid proteins is relatively conserved, and their biological functions are being confirmed. There is increasing evidence that the N protein will not only provide a specific diagnostic marker but also become an effective treatment target. In this study, 2G4, which specifically recognizes the N protein, was identified by screening a human phage display library. Based on the computer-guided homology modelling and molecular docking method used, the 3-D structures for the 2G4 scFv fragment (VH-linker-VL structure, with (G 4 S) 3 as the linker peptide in the model), SARS-CoV-2 N protein and its complex were modelled and optimized with a suitable force field. The binding mode and key residues of the 2G4 and N protein interaction were predicted, and three mutant antibodies (named 2G4-M1, 2G4-M2 and 2G4-M3) with higher affinity were designed theoretically. Using directed point mutant technology, the three mutant antibodies were prepared, and their affinity was tested. Their affinity constants of approximately 0.19 nM (2G4-M1), 0.019 nM (2G4-M2) and 0.075 nM (2G4-M3) were at least one order of magnitude lower than that of the parent antibody (3 nM; 2G4, parent antibody), as determined using a biolayer interferometry (BLI) assay. It is expected that high-affinity candidates will be used for diagnosis and even as potential therapeutic drugs for the SARS-CoV-2 pandemic.
【초록키워드】 Treatment, Structure, SARS-CoV-2, pandemic, Mutation, antibody, SARS-CoV-2 pandemic, diagnostic, peptide, Diagnosis, molecular docking, global pandemic, Protein, biological function, N protein, SARS-CoV-2 N protein, mutant, binding, Prevention and control, marker, Evidence, Interaction, genome sequence, complex, residue, candidate, homology, SARS-CoV-2 nucleocapsid, higher affinity, scFv, BLI, recent, effective, linker, shown, predicted, conserved, recognize, magnitude, expected, the N protein, the SARS-CoV-2, therapeutic drug, was tested, 【제목키워드】 antibody, nucleocapsid protein, Affinity maturation, the SARS-CoV-2,