1. Toward an Optimized Workflow for Middle-Down Proteomics
- Author
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Cristobal Gonzalez de Durana, Alba, Marino, Fabio, Post, Harm, van den Toorn, Henk W P, Mohammed, Shabaz, Heck, Albert J R, Biomolecular Mass Spectrometry and Proteomics, Sub Biomol.Mass Spectrometry & Proteom., Afd Biomol.Mass Spect. and Proteomics, Biomolecular Mass Spectrometry and Proteomics, Sub Biomol.Mass Spectrometry & Proteom., and Afd Biomol.Mass Spect. and Proteomics
- Subjects
0301 basic medicine ,Pore size ,Proteomics ,Proteases ,Mass spectrometry ,01 natural sciences ,Article ,Mass Spectrometry ,Analytical Chemistry ,03 medical and health sciences ,Small peptide ,Humans ,Overall performance ,Particle Size ,Chromatography ,Chemistry ,010401 analytical chemistry ,Peptide fragmentation ,0104 chemical sciences ,030104 developmental biology ,Biochemistry ,Proteome ,Peptides ,HeLa Cells ,Peptide Hydrolases - Abstract
Mass spectrometry (MS)-based proteomics workflows can crudely be classified into two distinct regimes, targeting either relatively small peptides (i.e., 0.7 kDa < Mw < 3.0 kDa) or small to medium sized intact proteins (i.e., 10 kDa < Mw < 30 kDa), respectively, termed bottom-up and top-down proteomics. Recently, a niche has started to be explored covering the analysis of middle-range peptides (i.e., 3.0 kDa < Mw < 10 kDa), aptly termed middle-down proteomics. Although middle-down proteomics can follow, in principle, a modular workflow similar to that of bottom-up proteomics, we hypothesized that each of these modules would benefit from targeted optimization to improve its overall performance in the analysis of middle-range sized peptides. Hence, to generate middle-range sized peptides from cellular lysates, we explored the use of the proteases Asp-N and Glu-C and a nonenzymatic acid induced cleavage. To increase the depth of the proteome, a strong cation exchange (SCX) separation, carefully tuned to improve the separation of longer peptides, combined with reversed phase-liquid chromatography (RP-LC) using columns packed with material possessing a larger pore size, was used. Finally, after evaluating the combination of potentially beneficial MS settings, we also assessed the peptide fragmentation techniques, including higher-energy collision dissociation (HCD), electron-transfer dissociation (ETD), and electron-transfer combined with higher-energy collision dissociation (EThcD), for characterization of middle-range sized peptides. These combined improvements clearly improve the detection and sequence coverage of middle-range peptides and should guide researchers to explore further how middle-down proteomics may lead to an improved proteome coverage, beneficial for, among other things, the enhanced analysis of (co-occurring) post-translational modifications.
- Published
- 2017
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