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. Author manuscript; available in PMC: 2018 Nov 28.
Published in final edited form as: J Proteome Res. 2016 Aug 3;15(9):3196–3203. doi: 10.1021/acs.jproteome.6b00414

Figure 2.

Figure 2.

Work flow for the identification and relative quantitation of histone H2B proteoforms from HeLa cells. A) Intact protein mass spectral segment for the 17+ charge state. Each isotopic distribution may present more than one H2B proteoform. B) Precursor ions of interest were isolated by an external quadrupole mass filter followed by in-cell SWIFT mass-selective excitation to within a nominal m/z range of ~1. C) Representative electron capture dissociation (ECD) product ion spectrum. Fragments are assigned based on a custom-input proteoform database by our custom software without prior deconvolution. Proteoform identification was then confirmed manually. D) Relative abundance ratios for corresponding fragments of different proteoforms from a given isolated precursor. E) Partial results of relative quantitation of histone H2B proteoforms.