Fig. 10

The phomasetin DAase Phm7 catalyzes the [4 + 2] cycloaddition reaction on the phomasetin-type linear triene substrate to generate desmethylphomasetin with a 2R,3 S,6R,11 S decalin moiety, while the equisetin DAase Fsa2 converts the identical substrate into a equisetin-type adduct, whose 2 S,3R,6 S,11R decalin ring is an enantiomer of that found in desmethylphomasetin, demonstrating the opposite stereoselectivity exerted by those two DAases [114]