Fig. 1: Identification of histone Kbz in yeast.

a Detection of the Kbz signals from core histones extracted from BY4742 yeast cells. The specificity of pan anti-Kbz was confirmed because it did not recognize any band from the E.coli whole-cell lysate (E.coli WCL) or recombinant Xenopus laevis histone octamer (Xl octamer) purified from E.coli. The H3* represents clipping H3. Source data for panels a–c are provided in the Source Data file. b Sodium benzoate treatment significantly enhanced the Kbz and Kac levels on yeast histones in a dose-dependent manner. BY4742 cells were grown in YPD to log phase, and then sodium benzoate was added into the medium for 6 h, followed by extraction of histones and western blotting analysis. c The level of histone Kbz was regulated by the type of carbohydrate. BY4742 cells were grown in standard medium with 2% glucose to log phase and then transferred to H₂O or other indicated mediums for 4 h, followed by extraction of histones and western blotting analysis. d Illustrations of all Kbz sites identified on core histones extracted from yeast cells treated with 10 mM sodium benzoate. The detected Kbz sites are shown in red. Nine Kbz sites detected in samples without sodium benzoate treatment are labeled by asterisks. Most Kbz sites overlap with the known Kac sites, except for H3K42, H3K115, and H4K44. e–h: MS/MS spectra of H3 and H4 peptides bearing Kbz modification. (e) H3K9; (f) H3K14; (g) H3K27; (h) H4K44. Predicted b- and y-type ions are listed above and below the peptide sequence, respectively. The circle symbol indicates the neutral loss of water. Matched ions are labeled in the spectra.