Differential Ion Mobility–Mass Spectrometry for Detailed Analysis of the Proteome

DMS can be used to rapidly separate ions prior to MS analysis. Compared to drift tube-based IMS, ion separation by DMS is more orthogonal to MS. The implementation of DMS in MS workflows has improved the coverage and quantification of proteomes, including the large-scale analysis of PTMs. High-resolution DMS can separate isobaric peptides that are otherwise challenging to separate by use of conventional chromatography methods, including peptides that differ by the position of a single methyl group. DMS combined with other gas-phase separation methods in tandem ion mobility can provide an alternative to LC, for exceptionally high-throughput proteomic analyses. The field of proteomics is increasingly concerned with the diversity and functional relevance of protein modifications. Differential ion mobility spectrometry (DMS) is emerging as a tool to detect and quantify additional peptide and protein species that are difficult to analyse with conventional instrumental methods. In this review, recent advances in DMS are discussed, with a focus on the different types of DMS instruments now available to researchers in proteomics. Furthermore, the combination of DMS with mass spectrometry (MS) for increased proteome coverage and the targeted analysis of modification patterns on single proteins is highlighted. Frontier areas of research, such as the analysis of intact proteoforms, and future directions for the implementation of DMS in proteomics are also discussed. The field of proteomics is increasingly concerned with the diversity and functional relevance of protein modifications. Differential ion mobility spectrometry (DMS) is emerging as a tool to detect and quantify additional peptide and protein species that are difficult to analyse with conventional instrumental methods. In this review, recent advances in DMS are discussed, with a focus on the different types of DMS instruments now available to researchers in proteomics. Furthermore, the combination of DMS with mass spectrometry (MS) for increased proteome coverage and the targeted analysis of modification patterns on single proteins is highlighted. Frontier areas of research, such as the analysis of intact proteoforms, and future directions for the implementation of DMS in proteomics are also discussed. an ion formed by noncovalent interactions between an ion with another molecule. in ion mobility, an area related to the size of an ion with respect to a given collision gas. in DMS, the electric field that compensates the ion trajectory from any deviation caused by the dispersion field. an isomer of a molecule that differs from another isomer by the rotation of one or more bonds in the molecule. the net difference between gas phase mobility of an ion in a high electric field and in a low electric field. the maximum electric field resulting from the alternating electric waveform in DMS, which deviates ion trajectory. the ratio between the maximum and minimum signal that can be used for the calculation of analyte concentration. the spatial mapping of biomolecules from solid surfaces using MS. an analytical technique that separates ions based on their mobility in a gas phase. The ion mobility is the drift velocity of an ion divided by the electric field strength to which the ion is subjected. the mass of an analyte divided by its number of charges. two chromatography methods are considered orthogonal if each can separate analytes that cannot be resolved by the other. the number of chromatographic peaks that can be resolved in a given separation time. a specific variant of a protein molecule, defined by the exact set of modifications (such as post-translational modifications) harboured by the protein. a protein or peptide ion of a given charge state can exist as an ensemble of different protonation isomers, in which the protons are distributed at different sites in the protein or peptide ion. a peptide that is specific to a unique protein sequence. a peptide that can be used to quantify a unique protein or proteoform. in DMS, the ratio between the CF at which an analyte transmits and the transmission peak width at half peak height. a LC technique whereby molecules are separated based on their charges. the online integration of two gas-phase ion separation methods to achieve 2D separation of analytes. in DMS, the successful passing of an analyte ion through the device electrodes.