Unravelling the SARS-CoV-
2 mechanism of entry
into host cells is engaging the endeavours of
researchers worldwide and, although angiotensin-converting
enzyme 2 (ACE2) is recognised as
the primary receptor, many issues remain to be
investigated.1
Remarkably, the interaction between ACE2 and the
spike (S) glycosylated protein of SARS-CoV-
2 necessary
for viral entry has been discovered by employing
crystallography. S protein presents a receptor binding
domain (RBD) and more specifically a receptor
binding motif (RBM) which mediates the attachment
to two virus-binding
hotspots within ACE2 surface.
The aminoacidic constitution of SARS-CoV-
2 RBM
is highly homologous to that of SARS-CoV
but shows
some differences, specifically a four-residue
motif at
482–485 (Gly-Val-
Glu-
Gly)
that confers more affinity
for ACE2 resulting in a tight relation between the two
molecules.
