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[Display omitted] • The structure and dynamics of the E2F1/DP1/DNA complex is modelled. • E2F1 and DP1 play a different role in the dynamics of the system. • DP1 flexibility may be relevant for protein–protein and protein-DNA interactions. The E2F1 transcription factor is a master regulator of cell-cycle progression whose uncontrolled activation contributes to tumor cells growth. E2F1 binds DNA as a heterodimer with DP partners, resulting in a multi-domain quaternary-structure complex composed of DNA binding domains, a coiled coil domain and a marked box domain separated by short linkers. Building on the 3D knowledge of the single domains of E2F and DPs, we characterized the structure and dynamics of the complete E2F1/DP1/DNA complex by a combination of small-angle X-ray scattering and molecular dynamics simulations. It shows an asymmetric contribution of the dynamics of the two proteins. Namely, the coiled-coil domain leans toward the DP1 side of the complex; the DP1 loop between α2 and α3 of the DBD partially populates a helical structure leaning far from the DNA and in the same direction of the coiled-coil domain; and the N-terminal disordered region of DP1, rich in basic residues, contributes to DNA binding stabilization. Intriguingly, tumor mutations in the flexible regions of the complex suggest that perturbation of protein dynamics could affect protein function in a context-dependent way. Our data suggest fundamental contributions of DP proteins in distinct aspects of E2F biology. [ABSTRACT FROM AUTHOR]

The trimeric CCAAT-binding NF-Y is a "pioneer" Transcription Factor -TF- known to cooperate with neighboring TFs to regulate gene expression. Genome-wide analyses detected a precise stereo-alignment ‐10/12 bp- of CCAAT with E-box elements and corresponding colocalization of NF-Y with basic-Helix-Loop-Helix (bHLH) TFs. We dissected here NF-Y interactions with USF1 and MAX. USF1, but not MAX, cooperates in DNA binding with NF-Y. NF-Y and USF1 synergize to activate target promoters. Reconstruction of complexes by structural means shows independent DNA binding of MAX, whereas USF1 has extended contacts with NF-Y, involving the USR, a USF-specific amino acid sequence stretch required for trans-activation. The USR is an intrinsically disordered domain and adopts different conformations based on E-box–CCAAT distances. Deletion of the USR abolishes cooperative DNA binding with NF-Y. Our data indicate that the functionality of certain unstructured domains involves adapting to small variation in stereo-alignments of the multimeric TFs sites. • DNA-binding cooperativity of NF-Y with USF1 relies on spatial configuration of TFBSs. • The structurally disordered domain USR (USF Specific Region) mediates cooperativity. • Multimeric TFs display structurally adapted protein interactions on DNA. [ABSTRACT FROM AUTHOR]