7SSA

Cryo-EM structure of pioneer factor Cbf1 bound to the nucleosome

7SSA の概要

• エントリーDOI: 10.2210/pdb7ssa/pdb
• EMDBエントリー: 25406
• 分子名称: Histone H3.2, Histone H4, Histone H2A.1, ... (7 entities in total)
• 機能のキーワード: transcription factor, basic helix-loop-helix, complex, gene regulation
• 由来する生物種: Xenopus laevis (African clawed frog); 詳細
• タンパク質・核酸の鎖数: 12
• 化学式量合計: 280357.92

構造登録者

Eek, P.,Tan, S. (登録日: 2021-11-10, 公開日: 2023-04-05, 最終更新日: 2024-06-05)

主引用文献

Donovan, B.T.,Chen, H.,Eek, P.,Meng, Z.,Jipa, C.,Tan, S.,Bai, L.,Poirier, M.G.
Basic helix-loop-helix pioneer factors interact with the histone octamer to invade nucleosomes and generate nucleosome-depleted regions.
Mol.Cell, 83:1251-1263.e6, 2023

PubMed Abstract: Nucleosomes drastically limit transcription factor (TF) occupancy, while pioneer transcription factors (PFs) somehow circumvent this nucleosome barrier. In this study, we compare nucleosome binding of two conserved S. cerevisiae basic helix-loop-helix (bHLH) TFs, Cbf1 and Pho4. A cryo-EM structure of Cbf1 in complex with the nucleosome reveals that the Cbf1 HLH region can electrostatically interact with exposed histone residues within a partially unwrapped nucleosome. Single-molecule fluorescence studies show that the Cbf1 HLH region facilitates efficient nucleosome invasion by slowing its dissociation rate relative to DNA through interactions with histones, whereas the Pho4 HLH region does not. In vivo studies show that this enhanced binding provided by the Cbf1 HLH region enables nucleosome invasion and ensuing repositioning. These structural, single-molecule, and in vivo studies reveal the mechanistic basis of dissociation rate compensation by PFs and how this translates to facilitating chromatin opening inside cells.

PubMed: 36996811
DOI: 10.1016/j.molcel.2023.03.006

実験手法

ELECTRON MICROSCOPY (3.2 Å)