Histone H2A Ubiquitination Reinforces Mechanical Stability and Asymmetry at the Single-Nucleosome Level

• DOI: 10.1021/jacs.9b12448
• Publication Date: 2020-01-31T20:07:25Z
• Authors: Xue Xiao; Cuifang Liu; Yingxin Pei; Yi-Zhou Wang; Jingwei Kong; Ke Lu; Lu Ma; Shuo-Xing Dou; Peng-Ye Wang; Guohong Li; Ping Chen; Wei Li
• Keywords: Histone octamer; Linker DNA; Chromatosome; Histone Methylation; Histone code

Monoubiquitination at lysine 119 of histone H2A (ubH2A) is a prevalent post-translational modification that associated with gene repression in the context chromatin. However, direct function ubH2A on nucleosome poorly understood. Here we identified effect using single-molecule magnetic tweezers. We revealed stabilizes by blocking peeling DNA from octamer. Each reinforces one-half outer wrap and introduces robust asymmetry for unfolding. Furthermore, real-time deubiquitination process confirmed ubH2A-nucleosome sequentially deubiquitinated restored to unmodified state. These results provide novel mechanism understand passage RNA or polymerases through barrier during transcription replication.