Structural insights into the histone H1-nucleosome complex as revealed by NMR

Friday, November 08, 2013 — Poster Session IV
2:00 p.m. – 4:00 p.m.	FAES Academic Center (Upper-Level Terrace)	NCI	STRUCTBIO-5

Authors

H. Feng
B. Zhou
H. Kato
D. Liang
D. Liang
Y. Yang
Y. Zhou
Y. Bai

Abstract

Linker H1 histones facilitate formation of higher-order structures of chromatin and play important roles in mitotic chromosome architecture and segregation. Despite several decades of studies, the structural basis of how H1 interacts with the nucleosome remains controversial. Here, we investigated Drosophila H1 in complex with the nucleosome containing 167 bp DNA centered with Widom ‘601’ sequence by combining solution NMR, spin-labeling, site-directed mutagenesis, isothermal titration calorimetry, and computational modeling. We find that the globular domain of H1 bridges the nucleosomal and linker DNA asymmetrically. The α3 helix of the globular domain interacts with the nucleosomal DNA at the vicinity of the dyad axis of the nucleosome while the α1 helix and the two β-strands bind to the 10 base pair linker DNA nearby. In addition, we find that two short regions in the C-terminal tail of H1 and the C-terminal tail of one of the two H2A histones are also involved in the H1 binding to the nucleosome. Our study provides a detailed structural characterization of the H1-nucleosome complex. The approach used here is applicable to the study of nucleosome-protein interactions in chromatin.