TY - JOUR TI - Cryo-EM structure of the SAGA and NuA4 coactivator subunit Tra1 at 3.7 angstrom resolution AU - Díaz-Santín, Luis Miguel AU - Lukoyanova, Natasha AU - Aciyan, Emir AU - Cheung, Alan CM A2 - Berger, James M VL - 6 PY - 2017 DA - 2017/08/02 SP - e28384 C1 - eLife 2017;6:e28384 DO - 10.7554/eLife.28384 UR - https://doi.org/10.7554/eLife.28384 AB - Coactivator complexes SAGA and NuA4 stimulate transcription by post-translationally modifying chromatin. Both complexes contain the Tra1 subunit, a highly conserved 3744-residue protein from the Phosphoinositide 3-Kinase-related kinase (PIKK) family and a direct target for multiple sequence-specific activators. We present the Cryo-EM structure of Saccharomyces cerevsisae Tra1 to 3.7 Å resolution, revealing an extensive network of alpha-helical solenoids organized into a diamond ring conformation and is strikingly reminiscent of DNA-PKcs, suggesting a direct role for Tra1 in DNA repair. The structure was fitted into an existing SAGA EM reconstruction and reveals limited contact surfaces to Tra1, hence it does not act as a molecular scaffold within SAGA. Mutations that affect activator targeting are distributed across the Tra1 structure, but also cluster within the N-terminal Finger region, indicating the presence of an activator interaction site. The structure of Tra1 is a key milestone in deciphering the mechanism of multiple coactivator complexes. KW - chromatin KW - transcription activation KW - coactivator KW - PIKK KW - SAGA KW - NuA4 JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -