SNAP output for PDB entry 7r5s [SNAP web server]

PDB-id

7r5s; SNAP-derived features in text and JSON formats; DNAproDB

Class

cell cycle

Method

cryo-EM (2.83 Å)

Summary

Structure of the human ccan bound to alpha satellite DNA

Reference

Yatskevich S, Muir KW, Bellini D, Zhang Z, Yang J, Tischer T, Predin M, Dendooven T, McLaughlin SH, Barford D (2022): "Structure of the human inner kinetochore bound to a centromeric CENP-A nucleosome." Science, eabn3810. doi: 10.1126/science.abn3810.

Abstract

Kinetochores assemble onto specialized centromeric CENP-A nucleosomes (CENP-A_Nuc) to mediate attachments between chromosomes and the mitotic spindle. We describe cryo-EM structures of the human inner kinetochore CCAN (Constitutive Centromere Associated Network) complex bound to CENP-A_Nuc reconstituted onto α-satellite DNA. CCAN forms edge-on contacts with CENP-A_Nuc, while a linker DNA segment of the α-satellite repeat emerges from the fully-wrapped end of the nucleosome to thread through the central CENP-LN channel that tightly grips the DNA. The CENP-TWSX histone-fold module further augments DNA binding and partially wraps the linker DNA in a manner reminiscent of canonical nucleosomes. Our study suggests that the topological entrapment of the linker DNA by CCAN provides a robust mechanism by which kinetochores withstand both pushing and pulling forces exerted by the mitotic spindle.