n281 in ACE binding pocket with Arg273 in ACE2 is likely to be responsible for the steric conflict (Guy et al., 2003; Towler et al., 2004). Another surprise of the ACE2 structure was its C-terminal domain, which—differently from ACE—revealed high homology with collectrin, a renal protein, which is involved in amino acids trafficking through the membrane (Yang et al., 2017).
FIGURE 1  Crysta