The N-terminal Tails of Histones H2A and H2B Adopt Two Distinct Conformations in the Nucleosome with Contact and Reduced Contact to DNA.
J Mol Biol
; 433(15): 167110, 2021 07 23.
Article
em En
| MEDLINE
| ID: mdl-34153285
ABSTRACT
The nucleosome comprises two histone dimers of H2A-H2B and one histone tetramer of (H3-H4)2, wrapped around by ~145 bp of DNA. Detailed core structures of nucleosomes have been established by X-ray and cryo-EM, however, histone tails have not been visualized. Here, we have examined the dynamic structures of the H2A and H2B tails in 145-bp and 193-bp nucleosomes using NMR, and have compared them with those of the H2A and H2B tail peptides unbound and bound to DNA. Whereas the H2A C-tail adopts a single but different conformation in both nucleosomes, the N-tails of H2A and H2B adopt two distinct conformations in each nucleosome. To clarify these conformations, we conducted molecular dynamics (MD) simulations, which suggest that the H2A N-tail can locate stably in either the major or minor grooves of nucleosomal DNA. While the H2B N-tail, which sticks out between two DNA gyres in the nucleosome, was considered to adopt two different orientations, one toward the entry/exit side and one on the opposite side. Then, the H2A N-tail minor groove conformation was obtained in the H2B opposite side and the H2B N-tail interacts with DNA similarly in both sides, though more varied conformations are obtained in the entry/exit side. Collectively, the NMR findings and MD simulations suggest that the minor groove conformer of the H2A N-tail is likely to contact DNA more strongly than the major groove conformer, and the H2A N-tail reduces contact with DNA in the major groove when the H2B N-tail is located in the entry/exit side.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
DNA
/
Histonas
Limite:
Humans
Idioma:
En
Revista:
J Mol Biol
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
Japão