1 research outputs found
Label-Free Relative Quantitation of Isobaric and Isomeric Human Histone H2A and H2B Variants by Fourier Transform Ion Cyclotron Resonance Top-Down MS/MS
Histone variants
are known to play a central role in genome regulation
and maintenance. However, many variants are inaccessible by antibody-based
methods or bottom-up tandem mass spectrometry due to their highly
similar sequences. For many, the only tractable approach is with intact
protein top-down tandem mass spectrometry. Here, ultra-high-resolution
FT-ICR MS and MS/MS yield quantitative relative abundances of all
detected HeLa H2A and H2B isobaric and isomeric variants with a label-free
approach. We extend the analysis to identify and relatively quantitate
16 proteoforms from 12 sequence variants of histone H2A and 10 proteoforms
of histone H2B from three other cell lines: human embryonic stem cells
(WA09), U937, and a prostate cancer cell line LaZ. The top-down MS/MS
approach provides a path forward for more extensive elucidation of
the biological role of many previously unstudied histone variants
and post-translational modifications