Table 3.

S-RBD-centered quartets and their interaction energies [kcal/mol]${}^{\mathrm{a}}$ with neighboring${}^{\mathrm{b}}$ hACE2 residues.

Quartet	SARS-CoV-1 S-RBD
	Residues	${\text{E}}_{\text{Int}}^{\text{DFT}}$	${\text{E}}_{\text{Int}}^{\text{DD}}$	${\text{E}}_{\text{Int}}^{\text{Total}}$
SQ1	ASN435-TYR436-ASN437-TYR438	$-$10.05	$-$3.40	$-$13.45
SQ2	LYS439-TYR440-LEU478-ASN479	$+$52.04	$-$4.09	$+$47.95
SQ3	PHE483-TYR484-THR485-THR486	$+$31.72	$-$20.90	$+$10.81
SQ4	PRO470-ALA471-LEU472-ASN473	$+$24.48	$-$8.99	$+$15.49
SQ5	THR425-ARG426-ASN427-ILE428	$-$55.25	$-$2.32	$-$57.57
SQ6	THR487-GLY488-TYR491-GLN492	$-$14.06	$-$28.08	$-$42.15
SQ7	TYR442-LEU443-TYR475-TRP476	$+$18.51	$-$17.02	$+$1.48

^aDFT energies computed at 6-311+G(d,p)/B3LYP level; Dispersion (DD) corrections evaluated with semiempirical method²⁷.

^bAll ACE2 residues within 4.5 $\mathrm{\AA }$ of each S-RBD quartet were included.