Fig. 2.

Maximum-likelihood phylogenetic tree of α/β hydrolases showing extant ACLs (red text) nested within a larger group of esterases (EST, blue text), the neighboring methylketone synthase (MKS, a decarboxylase, green text), and distantly related meta-cleavage product hydrolases (connected by dotted lines). Gray triangles represent clusters of proteins (numbers shown at the tips of the triangles). Resurrected ancestors EST1 and EST2 (blue) are dedicated esterases, EST3 (lavender) shows weak acetone cyanohydrin activity, ACL1 (purple) is an effective ACL with some esterase activity, whereas extant ACLs (red) are dedicated ACLs. Numbers at bifurcations and triangle bases represent bootstrap support.