Angiotensin converting enzyme 2 (ACE2)-B0AT1 amino acid transporter complex, molecular model. ACE2 is involved in the control of blood pressure. The membrane bound form of ACE2 is shown here as a ribbon structure (purple). Each of the two chains is 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 (brown). The combination stabilizes ACE2 in the membrane. Eventually, an enzyme cleaves ACE2 from its membrane stalk to give the soluble protease ACE2s.