DSSR-PyMOL cartoon-block schematics: PDB entry 7k60

PDB-id

7k60; DSSR-derived features in text and JSON formats

Class

nuclear protein-DNA

Method

cryo-EM (3.12 Å)

Summary

cryo-EM structure of a chromatosome containing human linker histone h1.10

Reference

Zhou BR, Feng H, Kale S, Fox T, Khant H, de Val N, Ghirlando R, Panchenko AR, Bai Y (2021): "Distinct Structures and Dynamics of Chromatosomes with Different Human Linker Histone Isoforms." Mol.Cell, 81, 166-182.e6. doi: 10.1016/j.molcel.2020.10.038.

Abstract

The repeating structural unit of metazoan chromatin is the chromatosome, a nucleosome bound to a linker histone, H1. There are 11 human H1 isoforms with diverse cellular functions, but how they interact with the nucleosome remains elusive. Here, we determined the cryoelectron microscopy (cryo-EM) structures of chromatosomes containing 197 bp DNA and three different human H1 isoforms, respectively. The globular domains of all three H1 isoforms bound to the nucleosome dyad. However, the flanking/linker DNAs displayed substantial distinct dynamic conformations. Nuclear magnetic resonance (NMR) and H1 tail-swapping cryo-EM experiments revealed that the C-terminal tails of the H1 isoforms mainly controlled the flanking DNA orientations. We also observed partial ordering of the core histone H2A C-terminal and H3 N-terminal tails in the chromatosomes. Our results provide insights into the structures and dynamics of the chromatosomes and have implications for the structure and function of chromatin.