Figure 5

Proposed catalytic mechanism in ACE (top) in contrast to predicted interactions in ACE3 (bottom). Four amino acid substitutions (in boxes) are rationalised to cause loss of activity in murine ACE3 (see text). Note: Gln391 can be flipped and interact either way with the hydroxyl groups of Thr361 and Ser363 as the hydroxyl group can act either as a hydrogen bond donor or as an acceptor.