Improved Methods for Comprehensive Assignment of Epigenetic Modification Configurations of Core Histone Proteins by High-Resolution ETD and HCD Mass Spectrometry

摘要

1) WCX-HILIC with ETD and HCD enables extensive separation and characterization of the differentially modified amino terminal tails of histone proteins. These methods also allow for detection of peptides that can differentiate between various histone isoforms. 2) Improvements to previously established WCX-HILIC methods include (1) the use of a solvent with reduced ionic strength and (2) the implementation of post-column addition to decrease the pH of the column eluate and increase protonation of precursors. 3) ETD and HCD generate complementary fragmentation information and can be used in combination to facilitate high sequence coverage of large histone peptides. 4) Aquisition of high-resolution MS/MS spectra enables unambiguous assignment of specific combinations of post-translational modifications to the amino terminal histone tails.