Fig. 4.
Determination of the spiro-forming enzyme for the biosynthesis of spirotryprostatin A. a A biomimetic synthesis for producing spirotryprostatin scaffold. b NotB-catalyzed semipinacol-type rearrangement in the biosynthesis of notoamide C. c The enzymatic function of FqzB in fumiquinazoline biosynthesis. d The BGC of tryprostatin/fumitremorgin. e The BGC of fumiquinazolines. f In vitro enzymatic reaction of FqzB with tryprostatins A and B. g FqzB-catalyzed ortho-quinonemethide formation is the crucial step in the spiro-ring formation