Histone post-translational modifications (PTMs) regulate protein transcription through chromatin remodeling and/or the recruitment of transcription factors. Although the number of known modifications is extensive, including acetylation (Lys), methylation (Lys/Arg), phosphorylation (Ser/Thr), and ubiquitination (Lys), advances in mass spectrometry have led to a quickly expanding epigenetic code. In an effort to identify novel histone PTMs, we have developed a precursor-ion scanning method that capitalizes on the consistent fragmentation of either Lys or Arg, regardless of the PTM status. This is achieved by proteolytically digesting chromatin to component amino acids and monitoring their fragmentation ions. To validate this methodology, we utilize SILAC cell lines treated with either low glucose (5mM) or high glucose (25mM), to identify both Lys and Arg modifications. By analyzing area ratios or precursor-ion masses between heavy and light samples, we observe significant alterations in both canonical PTMs (e.g. acetylation) as well as unknown precursor-ion masses. As a proof of concept, a mass shift of +72 Da was observed on both Lys and Arg and was found to be significantly elevated in high glucose samples. This is consistent with the reported mass of the glycolytic by-product methylglyoxal. In summary, this platform offers a simple discovery tool for the identification and characterization of histone PTMs.

LC-MS/MS discovery tool for the identification or histone posttranslational modifications

254th National Meeting (2017)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.