The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative pathogen of the ongoing coronavirus disease 2019 (COVID-19) pandemic, infects human hosts by binding with the human angiotensin-converting enzyme 2 (ACE2) receptor on their cells, notably the epithelium lining the respiratory tract. The receptor-binding domain (RBD) of the coronavirus spike protein binds to ACE2 followed by membrane fusion to the host cell, thus allowing the virus to infiltrate the cell and commence replication.
