Oxidation-guided and collision-induced linearization assists de novo sequencing of thioether macrocyclic peptides.

Oxidation of a thioether linkage in thioether-closed macrocyclic peptides led to collision-induced site-selective linearization of the peptides. This method has allowed for de novo sequencing of thioether macrocyclic peptides. The utility of the sequencing method was demonstrated by identifying the correct peptide sequences from a virtually randomized thioether macrocyclic peptide library.