Table 1.

Interaction of G-CK with amino acid residues of ACE2 (6M0J).

Protein	Compound	Binding Energy (kcal/mol)	H-Bond Interactions	Other Interactions	No. of H-Bond
ACE2	G-CK	−8.0	ASP350, ASP382, TYR385, ASN394, ARG393, HIS401	TRP349	6
	Dexamethasone	−7.8	SER47, ASP382, TYR385, HIS401	–	4
	Indinavir	−9.0	ALA348, ASP350, TYR385	THR347, TRP349, ASP382, ARG393, HIS401	3
	Remdesivir	−8.1	ASP206, LYS562	LEU95, TRP203, VAL209, PRO565	2
	Camostat	−7.4	SER43, ASP350, ASP382, TYR385, ASN394, HIS401	SER47, MET62, TRP349	6
	Chloroquine	−6.5	TYR196	TYR202, GLY205, GLU208, GLU564	1
	NAG	−6.2	ASP350, ASP382, TYR385, ARG393, HIS401	PHE40, ALA348	5

From the point of view of binding energy, as well as having almost similar H-bond and other types of interaction to the controls at the allosteric site of ACE2, G-CK shows strong interactions with the main host-based target ACE2 of the new coronavirus, showing G-CK might be a promising ACE2 inhibitor (Fig. 1). Hence, the G-CK and Dexamethasone in complex with ACE2 has been further utilized for molecular dynamics simulation to validate the docking scores and other properties.