Figure 4.

Applying the principles of diversity-generating biosynthesis to make novel compounds. A) In the precursor peptide, different recognition sequences are inserted before or after a designed core sequences, based upon the principle of substrate evolution. These recognition sequences are paired with cognate enzymes, following the principle of enzyme-RS pairs. Expression of the enzymes should follow the rule of inverted kinetic order. B) Example of manipulating RS elements in the total biosynthesis of the natural product, aeruginosamide B. RSI is fused to the N-terminus of TruD and heterocyclizes the cysteine residue of a short precursor peptide to thiazoline (green). AgeG recognizes and removes RSIII (red) from the tru pathway. AgeMTPT recognizes the N-terminus and C-terminus of the substrate and adds a prenyl and methyl group, respectively (purple).