Top-down and middle-down protein analysis reveals that intact and clipped human histones differ in post-translational modification patterns

摘要: Post-translational modifications (PTMs) of histone proteins play a fundamental role in regulation DNA-templated processes. There is also growing evidence that proteolytic cleavage N-terminal tails, known as clipping, influences nucleosome dynamics and functional properties. Using top-down middle-down protein analysis by mass spectrometry, we report H2B H3 tail clipping human hepatocytes demonstrate relationship between co-existing PTMs H3. Histones undergo processing primary the hepatocellular carcinoma cell line HepG2/C3A when grown spheroid (3D) culture, but not flat (2D) culture. tandem spectrometry localized four different sites one site H2B. We show culture clipped proteoforms are mainly represented canonical H3, whereas over 90% correspond to variant H3.3. Comprehensive revealed series PTMs, including K14me1, K27me2/K27me3, K36me1/me2, which differentially abundant intact Analysis negative crosstalk H3K36 methylation H3K23 acetylation Our data provide first carry distinct from those