Albany 2015:Book of Abstracts

Albany 2015
Conversation 19
June 9-13 2015
©Adenine Press (2012)

Structural Mechanisms of Nucleosome Recognition by Linker Histones

Linker histones bind to the nucleosome and regulate the structure of chromatin and gene expression. Despite more than three decades of effort, structural basis of nucleosome recognition by linker histones remains elusive. Here, we show the crystal structure of the globular domain of chicken linker histone H5 in complex with the nucleosome. In the structure, the globular domain sits on the dyad and interacts with both DNA linkers. Remarkably, we found that five key globular domain residues can discriminate the on-dyad binding from the off-dyad binding observed previously for the globular domain of Drosophila H1 linker histone. Our structure integrates results from mutation, cross-linking and fluorescence recovery after photobleach experiments, and helps resolve the long debate on structural mechanisms of nucleosome recognition by linker histones. Our findings also suggest that linker histones with different binding modes could fold chromatin to form distinct higher-order structures of chromatin.

Bing-Rui Zhou1
Jiansheng Jiang2
Rui Wang1
Hanqiao Feng1
Rodolfo Ghirlando3
T. Sam Xiao2
Yawen Bai1

1 Laboratory of Biochemistry and Molecular Biology
National Cancer Institute
2 Laboratory of Immunology
National Institute of Allergy and Infectious Diseases
3 Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases
National Institutes of Health
Bethesda, MD 20892, USA