Top-down characterization of engineered Bcl-xL proteoforms

Top-down fragmentation enables rapid characterization of phosphorylated proteins without extensive sample preparation and digestion. In this study, electron capture dissociation (ECD) was used to fragment proteoforms of the cell death-related protein, Bcl-xL. Using these methods, 85–90% sequence coverage was achieved for Bcl-xL proteoforms, allowing for effective localization of phosphorylation within minutes.