Computational and experimental identification of potential neutralizing peptides derived from human ACE2 against SARS-CoV-2 infection.

The human angiotensin-converting enzyme 2 (hACE2) is the primary receptor for the entry of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Some human alleles of ACE2 exhibit an improved affinity for the SARS-CoV-2 Spike protein. However, the impact of ACE2 polymorphisms on SARS-CoV-2 infection remains unclear. Our previous study predicted that G431 and S514 in the receptor-binding domain (RBD) of SARS-CoV-2 S1 domain are important for S protein stability, and that S protein residues G496 and F497 and ACE2 residues D355 and Y41 are critical for the RBD-ACE2 interaction. In this study, we explored the potential of hACE2-derived neutralizing peptides as a therapeutic strategy against SARS-CoV-2 and investigated how ACE2 polymorphisms affect RBD-ACE2 binding affinity. We applied computational saturation mutagenesis to systematically screen the binding affinity changes among all possible ACE2 missense mutations within the ACE2-Wuhan-S1 complex. Mutations at ACE2 residues D355 and Y41 were predicted to weaken binding affinity, whereas those at N330 and D30 enhanced it. We identified six ACE2 regions (19-49, 65-102, 320-333, 348-359, 378-395, and 552-563) to be vital for ACE2-RBD interaction. We synthesized peptides corresponding to these six regions and tested them using a pseudotyped viral particle system and dot blot assay. Three peptides were confirmed to bind with the S protein, and four exhibited inhibitory effects. We aligned ACE2-Wuhan-S1 and ACE2-Omicron-S1 complexes, conducted correlation analysis, and observed similar binding patterns, suggesting that these peptides also have the potential to neutralize Omicron strains.IMPORTANCESARS-CoV-2 continues its global spread. In this research, we identified six regions within ACE2 that are vital for interaction with the viral S receptor-binding domain and have the potential to neutralize SARS-CoV-2 infection. Among the six peptides derived from ACE2, three were confirmed to bind with the S protein of the Wuhan strain, and four exhibited inhibitory effects on the Wuhan strain SARS-CoV-2. We also found ACE2 residues D355 and Y41 as weakening affinity, and N330 and D30 as enhancing it. We also aligned this complex with the ACE2-Omicron-S1 complex, performed correlation analyses, and compared their patterns of stability changes upon mutations and obtained similar results, indicating that these peptides may also be effective against Omicron variants. These results provide insight into the role of ACE2 polymorphism in viral entry and suggest that hACE2-derived peptides may offer a promising therapeutic strategy against SARS-CoV-2, demonstrating strong consistency between our computational predictions and experimental outcomes.