Table 1.

The binding scores and interactions of the examined FDA-approved antidepressant drugs (1–8) and the docked co-crystallized inhibitors (9) of M^pro pocket inside the S and M^pro binding sites of both SARS-CoV-2 and MERS-CoV.

No	Drug	Ra	SARS-CoV-2		MERS-CoV
			Sb	Interactions	Sb	Interactions
1	Amitriptyline	S	− 6.34	Thr347/pi-H Thr347/pi-H	− 6.35	Lys470/H-acceptor
		Mpro	− 5.88	Tyr154/pi-H	− 6.15	–
2	Citalopram	S	− 6.44	His345/pi-pi	− 6.78	Ser426/H-acceptor Gln471/H-acceptor Lys470/pi-H
		Mpro	− 6.63	Tyr154/pi-H	− 6.32	–
3	Escitalopram	S	− 6.51	–	− 6.62	Gln471/H-acceptor
		Mpro	− 6.38	Tyr154/pi-pi	− 7.10	Met168/H-acceptor
4	Eszopiclone	S	− 6.87	Ala348/H-acceptor His345/H-acceptor His345/pi-pi	− 6.70	Gln471/pi-H Lys470/pi-H
		Mpro	− 6.54	Arg298/H-acceptor Ser123/pi-H Tyr118/pi-pi	− 7.26	–
5	Imipramine	S	− 6.52	Ala348/H-acceptor His345/pi-pi	− 6.00	Gln471/H-acceptor
		Mpro	− 6.00	–	− 6.29	Gly149/H-acceptor
6	Mirtazapine	S	− 5.65	Thr347/pi-H	− 6.44	–
		Mpro	− 5.50	Tyr154/pi-H Tyr154/pi-pi	− 6.00	–
7	Paroxetine	S	− 6.62	–	− 6.79	Ser457/H-donor
		Mpro	− 6.03	–	− 6.99	His166/pi-H
8	Sertraline	S	− 6.01	His345/pi-pi	− 6.17	Gln471/pi-H
		Mpro	− 5.57	Tyr154/pi-H	− 5.99	–
9	Co-crystallized inhibitor	Mpro	− 8.47	Gln192/H-donor Asn142/H-acceptor Met49/H-donor	− 7.58	Glu169/H-acceptor His166/pi-H
					− 7.89	His166/pi-H Phe143/H-pi

S, the spike protein; M^pro, the main protease receptor.

^aThe receptor pocket.

^bThe score of a ligand inside the binding pocket (Kcal/mol).