Computational study of the molecular interactions in the binding of coronavirus Spike-proteins with the human Angiotensin-Converting Enzyme 2 (ACE2) cellular receptor

Due to the pandemic urgency of COVID-19, we investigated the molecular interaction of the Spike-proteins (Sp) from SARS-CoV and SARS-CoV-2 with the human Angiotensin-Converting Enzyme 2 (ACE2), recognized as the most relevant cellular receptor involved in both the coronavirus infections. SARS-CoV-2 Sp consists of a long sequence of 1273 amino acids, and the interaction with ACE2 receptor is due to its region 318-510, named Receptor-Binding Domain (RBD). On the other side, ACE2 consists of 805 amino acids and its physiological activity as peptidase regulates cardiovascular homeostasis. The interaction between ACE2 and Sp-RBD is described at atomic level by different crystallographic complexes obtained under different conditions, and available in the RCSB PDB Protein DataBank. We in silico analyzed the structural features of the Sp-ACE2 complexes and observed the surface interactions occurring in the different complex structures. The results of the comparative analysis highlight the details of the most peculiar interactions and the corresponding amino acids involved.