On the basis of the neutralizing antibody in the RBD region of the SARS-CoV-2S protein, the Fab segment of the neutralizing antibody is prepared through recombinant expression, the Fab segment reacts with the RBD region of the SARS-CoV-2S protein to form an antigen-antibody compound, and purification, crystallization and X-crystal diffraction analysis are performed. The method comprises the following steps: analyzing an antigen-antibody compound structure by using a homologous compound three-dimensional structure in a PDB database as a model to obtain amino acid residues interacting with a neutralizing antibody on SARS-CoV-2S protein RBD, carrying out site-specific mutagenesis on key amino acid residues, and detecting the affinity of an SARS-CoV-2S protein RBD mutant and the neutralizing antibody Fab. And determining the epitope peptide fragment according to the influence degree of the RBD point mutation on the affinity. The invention also provides application of the epitope peptide fragment in preparation of a fusion antigen for detecting SARS-CoV-2, and application of the epitope peptide fragment in preparation of an immunogen for preparing a vaccine or an antibody.
Neutralizing epitope peptide in RBD region of SARS-CoV-2 S protein and application of neutralizing epitope peptide