(333–526) and SARS-COV includes 190 residues (323–512). ACE2 protein contains 597 residues (19–615) in the complex structure for both systems. All the structures including nCOV-2019, SARS-COV, and all 21 alanine substitutions of nCOV-2019 were prepared and solvated in GROMACS.35 A TIP3P water model was used for the solvent and Param99SB-ILDN