Complex of SARS-CoV-2 spike protein bonding domain and angiotensin converting enzyme 2 (ACE2)-B0AT1 amino acid transporter, molecular model. The membrane-bound form of angiotensin 2 (ACE2m), is the point of attack by several coronaviruses, including SARS-CoV-2 the cause of covid-19. This illustration shows the two subunits of ACE2m (green) in a complex with the receptor bonding domain of the SARS-CoV-2 spike protein (orange). The two ACE2m protein chains are embedded in the membrane by a single strand of helix. In this study, ACE2 was co-crystallized with another membrane protein, an amino acid transporter, B0AT1 (blue). The combination stabilizes ACE2 in the membrane.