Background: COVID-19 has become a pandemic with higher morbidity and mortality rates
after its start from Wuhan city of China. The infection by RNA virus, also known as SARS-CoV-2 or
2019-nCoV, from the beta class of coronaviruses, has been found to be responsible for COVID-19.
Structural analysis and evidences have been indicated that interaction between a segment of receptor
binding domain (RBD) from S protein of the virus and human angiotensin-converting enzyme 2
(hACE2) is essential for cellular entry of the virus.
Objective: The current review sheds light on structural aspects for the inhibition of RBD-hACE2 interaction
mediated cellular entry of SARS-CoV-2.
Methods: The present study provides a critical review of recently published information on RBDhACE2
interaction and its inhibitors to control SARS-CoV-2 infection. The review highlighted the
structural aspects of the interaction between RBD-hACE2 and involved amino acid residues.
Results: Recently, several studies are being conducted for the inhibition of the SARS-CoV-2 attachment
and entry to the human cellular system. One of the important targets for viral invasion is its
binding with cell surface receptor, hACE2, through RBD on S-protein. Mimicking of three residues
on ACE2 (Lys31, Glu35 and Lys353 on B chain) provided a hot target directed strategy for the inhibition
of early attachment of the virus to the cell. Early screening of peptidic or non-peptidic molecules
for the inhibition of RBD-hACE2 interaction has raised the hope for potential therapeutics against
COVID-19. The higher affinity of molecules toward RBD than ACE2 is an important factor for selectivity
and minimization of ACE2 related adverse events on the cardiovascular system, brain, kidney,
and foetus development during pregnancy.
Conclusion: Inhibition of RBD-hACE2 interaction by different molecular scaffolds can be used as a
preferred strategy for control of SARS-CoV-2 infection. Recently, published reports pointed out
Lys31, Glu35 and Lys353 on the B chain of ACE2 as crucial residues for mimicking and design of
novel molecules as inhibitors SARS-CoV-2 attachment to human cells. Moreover, some recently identified
RBD-hACE2 interaction inhibitors have also been described with their protein binding pattern
and potencies (IC50 values), which will help for further improvement in the selectivity.