Nucleosome dyad determines the H1 C-terminus collapse on distinct DNA arms.
Fiche publication
Date publication
décembre 2022
Journal
Structure (London, England : 1993)
Auteurs
Membres identifiés du Cancéropôle Est :
Dr HAMICHE Ali, Dr KLAHOLZ Bruno
Tous les auteurs :
Louro JA, Boopathi R, Beinsteiner B, Mohideen Patel AK, Cheng TC, Angelov D, Hamiche A, Bendar J, Kale S, Klaholz BP, Dimitrov S
Lien Pubmed
Résumé
Nucleosomes are symmetric structures. However, binding of linker histones generates an inherently asymmetric H1-nucleosome complex, and whether this asymmetry is transmitted to the overall nucleosome structure, and therefore also to chromatin, is unclear. Efforts to investigate potential asymmetry due to H1s have been hampered by the DNA sequence, which naturally differs in each gyre. To overcome this issue, we designed and analyzed by cryo-EM a nucleosome reconstituted with a palindromic (601L) 197-bp DNA. As in the non-palindromic 601 sequence, H1 restricts linker DNA flexibility but reveals partial asymmetrical unwrapping. However, in contrast to the non-palindromic nucleosome, in the palindromic nucleosome H1 CTD collapses to the proximal linker. Molecular dynamics simulations show that this could be dictated by a slightly tilted orientation of the globular domain (GD) of H1, which could be linked to the DNA sequence of the nucleosome dyad.
Mots clés
cryo-EM, linker histone H1, molecular dynamics, nucleosome
Référence
Structure. 2022 12 26;: