Fig. 2. MALDI-TOF-MS spectra of example modified cyclic peptides. For each spectrum, the peptide sequence is shown above, with modified amino acids emphasised in bold, and the modifications are indicated in the cartoon structure to the left. (A) Thioether cyclised peptide with a single modification inside the macrocycle with thio-Glc. The struck-through peak is from a DBAA cross-linked side-product wherein translation started from the second codon. (B) Thioether cyclised peptide modified both inside and outside the macrocycle with thio-Glc. (C) Bis-amide cyclised peptide with a single modification inside the macrocycle with thio-Glc. Products are marked with colour-coded arrows as follows: blue for eliminated cysteine (Dha-containing peptide), orange for the conjugate addition product(s), and magenta for cysteines cross-linked with DBAA (see Fig. S7†). Calculated and observed values are for the final products, being the rightmost peak in each case.