Fig. 8. Analysis of the acceptance of the Tcp12 C-domain for different hexapeptide substrates, either the standard linear hexapeptide (L-4), a peptide bearing altered stereochemistry at the C-terminal residue (D-4) and a monocyclic version of L-4 (Mono-4) formed through the actions of OxyBvan. (A) Initial formation of Mono-4 was performed on PCP6 using OxyBvan and an appropriate redox system. (B) Comparison of the rate of cyclisation of these three peptides under identical reaction conditions shows that the L-4 peptide is accepted significantly faster than the d-configured form of this peptide (half conversion at 30 seconds vs. 15 minutes), whilst the cyclised peptide Mono-4 is only accepted for peptide extension at a very slow rate (half conversion > 200 minutes).
