Structure
Volume 16, Issue 7, 9 July 2008, Pages 1077-1085
Journal home page for Structure

Article
Structural Basis for the Recognition of Histone H4 by the Histone-Chaperone RbAp46

https://doi.org/10.1016/j.str.2008.05.006Get rights and content
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Summary

RbAp46 and RbAp48 (pRB-associated proteins p46 and p48, also known as RBBP7 and RBBP4, respectively) are highly homologous histone chaperones that play key roles in establishing and maintaining chromatin structure. We report here the crystal structure of human RbAp46 bound to histone H4. RbAp46 folds into a seven-bladed β propeller structure and binds histone H4 in a groove formed between an N-terminal α helix and an extended loop inserted into blade six. Surprisingly, histone H4 adopts a different conformation when interacting with RbAp46 than it does in either the nucleosome or in the complex with ASF1, another histone chaperone. Our structural and biochemical results suggest that when a histone H3/H4 dimer (or tetramer) binds to RbAp46 or RbAp48, helix 1 of histone H4 unfolds to interact with the histone chaperone. We discuss the implications of our findings for the assembly and function of RbAp46 and RbAp48 complexes.

PROTEINS
DNA

Cited by (0)

3

These authors contributed equally to this work

4

Present address: Molecular and Structural Biology Division, Central Drug Research Institute, Chattar Manzil Palace, Lucknow 226 010, India

5

Present address: Cancer Research UK, Lincoln's Inn Fields Laboratories, London WC2A 3PX, UK