7X3T

Cryo-EM structure of ISW1a-dinucleosome

Summary for 7X3T

• Entry DOI: 10.2210/pdb7x3t/pdb
• EMDB information: 32992
• Descriptor: Histone H3, BERYLLIUM TRIFLUORIDE ION, MAGNESIUM ION, ... (11 entities in total)
• Functional Keywords: ioc3 binding, protein binding
• Biological source: Xenopus laevis (African clawed frog); More
• Total number of polymer chains: 20
• Total formula weight: 634524.56

Authors

Lifei, L.,Kangjing, C.,Chen, Z. (deposition date: 2022-03-01, release date: 2023-09-20, Last modification date: 2024-02-28)

Primary citation

Li, L.,Chen, K.,Sia, Y.,Hu, P.,Ye, Y.,Chen, Z.
Structure of the ISW1a complex bound to the dinucleosome.
Nat.Struct.Mol.Biol., 31:266-274, 2024

PubMed Abstract: Nucleosomes are basic repeating units of chromatin and form regularly spaced arrays in cells. Chromatin remodelers alter the positions of nucleosomes and are vital in regulating chromatin organization and gene expression. Here we report the cryo-EM structure of chromatin remodeler ISW1a complex from Saccharomyces cerevisiae bound to the dinucleosome. Each subunit of the complex recognizes a different nucleosome. The motor subunit binds to the mobile nucleosome and recognizes the acidic patch through two arginine residues, while the DNA-binding module interacts with the entry DNA at the nucleosome edge. This nucleosome-binding mode provides the structural basis for linker DNA sensing of the motor. Notably, the Ioc3 subunit recognizes the disk face of the adjacent nucleosome through interacting with the H4 tail, the acidic patch and the nucleosomal DNA, which plays a role in the spacing activity in vitro and in nucleosome organization and cell fitness in vivo. Together, these findings support the nucleosome spacing activity of ISW1a and add a new mode of nucleosome remodeling in the context of a chromatin environment.

PubMed: 38177688
DOI: 10.1038/s41594-023-01174-6

Experimental method

ELECTRON MICROSCOPY (5.4 Å)