– The spike protein (S) of coronavirus (CoV) attaches the virus to its cellular receptor, angiotensin-converting enzyme 2 (ACE2). A defined receptor-binding domain (RBD) on S mediates this interaction.The S protein plays key parts in the induction of neutralizing-antibody and T-cell responses, as well as protective immunity. SARS-COV-2 Spike RBD Protein (hFc & Avi), Biotinylated is expressed in HEK293 mammalian cells with C-hFc-Avi tag. The predicted molecular weight is 51.7 kDa and the accession number is A0A6G7K2L4.