Table 2.

Binding energy scores and molecular interactions between top 5 leads and SARS-CoV M^pro. The figures in bracket indicate the hydrogen bond length.

ZINC ID	Common Name	Structure	Binding Energy (kcal/mol)	Molecular Interactions
				Hydrogen bonds	Hydrophobic interactions
ZINC000026985532	Saquinavir		−9.6	O6…..N(Glu166) [2.83 Å] N5…..OE1(Gln189) [3.06 Å] O2…..O(Leu141) [2.75 Å] O1…..N(Gly143) [2.89 Å]	Thr25,Thr26, His41,Met49, Phe140, Asn142, Cys145, His164, Met165, Leu167, Thr190 and Gln192 (N = 12)
ZINC000052955754	Ergotamine		−9.5	O1…..N(Gly143) O4…..N(Gly143)	Thr25, His41, Met49, Asn142, Cys145, His164, Met165, Glu166 and Gln189 (N = 9)
ZINC000006716957	Nilotinib		−9.4	N4…..OD(Asn142) [3.03 Å] N1…..O(His164) [3.15 Å]	Thr25, His41, Cys44, Met49, Phe140, Cys145, His163, Met165, Glu166 and Gln189 (N = 10)
ZINC000013831130	Raltegravir		−9.2	O4…..O(His41) [2.95 Å] O2…..N(Cys145) [3.25 Å] N5…..OD1 (Asn142) [2.83 Å]	Thr25, Thr26, Leu27, Cys44, Met49, Leu141, Gly143, Asp187, Arg188 and Gln189, (N = 10)
ZINC000003978005	Dihydroergotamine		−9.2	O4…..N(Ser144) [3.34 Å] O4…..N(Gly143) [2.67 Å] O1…..N(Gly143) [2.98 Å]	Thr25, Leu27, His41, Cys44, Met49, Asn142, Cys145, His164, Met165, Glu166 and Gln189 (N = 11)
Control (G85)	SG85		−7.9	O19…..N(Cys145) [3.20 Å] O19…..SG(Cys145) [3.28 Å] N49…..OE1(Gln189) [2.89 Å] O47…..N(Glu166) [3.02 Å]	Thr25, Thr26, His41, Met49, Phe140, Leu141, Asn142, Gly143, Ser144, His163, His164, Met165, Asp187, Thr190, Ala191 and Gln192 (N = 16)