Fig. 2

ACE2 3D-structure and isoforms. a 3D structure of ACE2 adopted from Towler et al. [36] and drawn in iCn3D using PBD ID: 1R4L. The structure was modified based on the newly identified N-glycosylation sites labeled in black. b ACE2 exists in 4 different isoforms along with a soluble form cleaved at residues 716–741 and constitutes 555 amino acids lacking the transmembrane collectrin homology domain. ACE2 isoform 2 shows a truncation of the full-length ACE2 with 100% homology in the 786 residues. ACE2 isoform 3 displays deletions in the transmembrane and collectrin homology domains leading to 95% similarity with ACE2 represented by gradient color in the corresponding domains. The fourth isoform with shorter N-terminus, lacking the carboxypeptidase activity and inability to bind to SARS-CoV-2. SP signal peptide