生物大分子室级学术报告-Structure and regulation of chromatin remodelers
报告人： 陈柱成 教授，清华大学
主持人：周 政 研究员
Chromatin remodelers control a myriad of nucleic acid transactions by sliding, removing and reconstructing nucleosomes in eukaryotic cells. They share two RecA-like core domains, which couple ATP hydrolysis and DNA translocation to chromatin remodeling. The activity of the catalytic core is regulated by different auxiliary domains in different remodelers, leading to distinct biological functions of these proteins inside the cells. The crystal structures of Snf2 and ISWI from the yeast Myceliophthora thermophila show that the two RecA-like core domains of Snf2 stack together and twist their ATP-binding motifs away from each other, explaining the inactivity of the protein in the ground state. The bare catalytic core of Snf2 shows a high chromatin-remodeling activity, which is suppressed by the N-terminal HSA domain. In contrast, ISWI is inhibited by its N-terminal AutoN domain, which contains two inhibitory elements and tightly holds the enzyme in an inactive conformation. The C-terminal NegC domain is involved in binding to the core2 domain and functions as an allosteric element for ISWI in sensing the length of extranucleosomal DNA. Comparison of the structures of different of the overall architectures and regulation logics of these remodelers reveals conservation of the individual core domains, and yet distinct features.