The emergence of the eukaryotes coincided with the diversification of histone proteins and their post-translational modifications by enzymes that constitute the core of eukaryotic chromatin. Yet the e...

Ranawat et al. show the cryo-EM structures of Asgard archaeal chromatin assemblies, revealing that the histone HHoB assembles into both compact closed and extended open hypernucleosomes. The closed co...

DNA-wrapping histone proteins play a central role in chromatin organization, gene expression and regulation in most eukaryotes and archaea. While the …

Ranawat et al. show the cryo-EM structures of Asgard archaeal chromatin assemblies, revealing that the histone HHoB assembles into both compact closed and extended open hypernucleosomes. The closed conformation is conserved across archaea, while the open conformation represents an Asgard-specific innovation.