Figure 12.

Post-core enzyme modifications by redox enzymes. (A) Biosynthetic pathway of Py-469 highlights three consecutive redox enzymes in modifying benzene ring to 2,3-epoxy-1,4-cyclohexane diol. The relative stereochemistry was determined by MicroED. (B) Multitude of redox enzymes in the biosynthesis of trichoxide reveals a unique strategy to synthesize aromatic polyketide structure using HRPKS. A similar pathway was also found in sodarial biosynthesis. (C) Structure of tetrotodoxin, which is an orthoester containing natural product. (D) Simplified biosynthetic pathway of novofumigatonin. The structure is highly oxygenated with a series of oxygen-handling enzymes, in particular the formation of orthoester functional group by two non-heme iron enzymes, NvfE and NvfF.