SARS-CoV-2 Furin Site Blocking Polyclonal Antibody

SARS-CoV-2 harbors a unique furin cleavage site at the boundary between the S1 and S2 subunits of its spike protein, which can be cleaved by the proprotein convertase (PC) furin and furin-like PCs. Proteolytic activation of SARS-CoV-2 spike protein at the S1/S2 boundary facilitates interaction with host ACE2 receptor for cell entry. The complete SARS-CoV-2 furin cleavage site has been characterized as a 20 amino acid motif corresponding to the amino acid sequence A672- S691 of SARS-CoV-2 spike protein, with one core region SPRRAR?SV (8 amino acids, S680- V687) and two flanking solvent-accessible regions (8 amino acids, A672û N679, and 4 amino acids, A688- S691). The core region is very unique as its R683 and A684 positions are positively-charged (Arg) and hydrophobic (Ala) residues, respectively, which could be cleaved by furin and/or furin-like PCs secreted from host cells and bacteria in the airway epithelium. Furin and furin-like PCs, such as PC5/6A and PACE4, are proven to be cleavage region sequence-specific, and these PCs exhibit widespread tissue distribution.