Figure 6.

Scaffold generation for a hypothetical mixed cluster. The NRP positions are marked α for the N-C-rest and β for the ketone following the PK nomenclature. The substrate specificity leads to a modification in the α-position. The module arrangement results in a modification in the β-position. Each parameter and corresponding modification is color-coded. Loading modules do not add a carbon atom in the β-position, marked with a dashed box (β₁). Terminal modules add an additional carboxyl (TE) or hydroxyl (TD) substructure to the scaffold. Epi. refers to the epimerization of the NRP substrates, resulting in L- or D-forms.