What are the main structural differences of SARS-CoV-1 and
-2?
The spike protein of SARS-CoV-2 has a receptor-binding domain that binds
ACE2 with higher affinity than SARS-CoV.8 In addition,
the SARS-CoV-2 spike protein harbors a polybasic furin cleavage site
(PRRAR) with an insertion of 4 amino acid residues, which is distinct
from that found in SARS-CoV and other SARS-like viruses. This allows
effective cleavage by furin and other proteases and determines viral
infectivity and host range.6