Expression and purification of soluble human ACE2
DNA fragments encoding residues 19-615 of human hACE2 with N-terminal FLAG and 6×his tags were cloned between Sal I and Hind III of modified pFASTBac1 vector with gp67 signal peptide. The soluble receptors were expressed in High Five insect cells using the bac-to-bac system (Invitrogen) and purified using nickel affinity and ion-exchange chromatography.