Post-translational modifications (PTMs) are critical to the activity of most proteins. Their importance derives from the structural changes they induce. PTM of an amino acid residue side-chain alters the intra- and intermolecular interactions in which it participates.  The consequences are modulations of peptide/protein conformation. In the gas-phase, these conformational changes are reflected in the ion's mobility. Isomeric post-translationally modified peptides exist widely in bottom-up proteomics as both localisation variants (i.e., those with identical sequence but differing sites of modification) and sequence variants. We have shown that FAIMS is capable of separating simple mixtures of isomeric post-translationally modified peptides, and separation can be confirmed by ETD mass spectrometry. The advantage of ETD over more established MS/MS techniques is retention of labile PTMs on peptide backbone fragments, i.e., ETD provides ions diagnostic of the precursor isomer.  Recent developments in the application of FAIMS to the analysis of phosphopeptides and glycopeptides are discussed.

High field asymmetric waveform ion mobility spectrometry (FAIMS) and electron transfer dissociation (ETD) mass spectrometry for the analysis of post-translationally modified peptides

244th National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.