Selection Criteria: The submitted conformers are the 20 structures with the lowest restraint energies, restraint violations, and RMS deviations from ideal covalent geometry 
Primary Citation of Related Structures:   1S5Q, 1S5R
PubMed Abstract: 
Recruitment of the histone deacetylase (HDAC)-associated Sin3 corepressor is an obligatory step in many eukaryotic gene silencing pathways. Here we show that HBP1, a cell cycle inhibitor and regulator of differentiation, represses transcription in a HDAC/Sin3-dependent manner by targeting the mammalian Sin3A (mSin3A) PAH2 domain ...
Recruitment of the histone deacetylase (HDAC)-associated Sin3 corepressor is an obligatory step in many eukaryotic gene silencing pathways. Here we show that HBP1, a cell cycle inhibitor and regulator of differentiation, represses transcription in a HDAC/Sin3-dependent manner by targeting the mammalian Sin3A (mSin3A) PAH2 domain. HBP1 is unrelated to the Mad1 repressor for which high-resolution structures in complex with PAH2 have been described. We show that like Mad1, the HBP1 transrepression domain binds through a helical structure to the hydrophobic cleft of mSin3A PAH2. Notably, the HBP1 helix binds PAH2 in a reversed orientation relative to Mad1 and, equally unexpectedly, this is correlated with a chain reversal of the minimal Sin3 interaction motifs. These results not only provide insights into how multiple, unrelated transcription factors recruit the same coregulator, but also have implications for how sequence similarity searches are conducted.
Related Citations: 
Solution Structure of the Interacting Domains of the Mad-Sin3 Complex: Implications for Recruitment of a Chromatin-Modifying Complex Brubaker, K., Cowley, S.M., Huang, K., Loo, L., Yochum, G.S., Ayer, D.E., Eisenman, R.N., Radhakrishnan, I. (2000) Cell 103: 655
Organizational Affiliation: 
Department of Biochemistry, Molecular Biology, and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500, USA.
Selection Criteria: The submitted conformers are the 20 structures with the lowest restraint energies, restraint violations, and RMS deviations from ideal covalent geometry