Cryo-EM reveals open and closed Asgard chromatin assemblies. Ranawat et al.

This dataset is linked to the manuscript "Cryo-EM reveals open and closed Asgard chromatin assemblies" by Ranawat et al.
It provides raw images related to biochemical analysis in this paper (electrophoretic mobility shift assays), and cryo-EM images that were used for helical parameter quantification.

The manuscript itself reports the first structural characterization of Asgard chromatin assemblies formed by the Hodarchaeal histone HHoB. Using high-resolution cryo-EM, we show that this histone organizes DNA into two distinct forms: a compact “closed” hypernucleosome and an extended “open” hypernucleosome. The closed conformation appears conserved across archaeal lineages, whereas the open state resembles the eukaryotic H3–H4 octasome and likely represents an Asgard-specific innovation. We further demonstrate that Mg²⁺ ions modulate these conformations, pointing to a potential regulatory mechanism. Together, these findings provide the first structure-based model of Asgard chromatin organization and offer new insights into the evolution of chromatin architecture.