A range of macrocycle sizes can be generated, and a variable number of heterocycle rings incorporated into the product. 

The final macrocycle may contain 0-6 heterocycles, with the only requirement being that the final residue in the incorporated substrate is cyclic (Pro, ThH, OxH, Thz, Oxz). Unmodified Ser/Thr/Tyr/Trp may be further modified by the addition of a prenyl group.

Shown below are 18 different macrocycles with ring sizes including 6 (blue), 7 (red), 8 (black), 9 (purple) residues, with 2 – 4 heterocycles, plus incorporation of a selenazoline (green) ring.  These compounds have been characterised in publications from the company’s founder scientists:

“An Enzymatic Route to Selenazolines”, Jesko Koehnke et al., ChemBioChem, 2013, 14, 564
“An Efficient Method for the In Vitro Production of Azol(in)e-Based Cyclic Peptides”, Wael E. Houssen et al., Angew Chem, 2014, 53, 14171

(click image to zoom)

Other macrocycles have been made incorporating residues with chemical groups suitable for further chemical modification