Fig. 1: Structure of a ASCC3^HR–TRIP4 complex.

a Schemes of regions or domains in ASCC3 and TRIP4. Numbers above the schemes, region/domain borders. NTR N-terminal region, NC/CC N-terminal/C-terminal cassettes, HR helicase region, ZnF zinc finger domain, Lasso lasso peptide, ASCH ASC−1 homology domain. b SDS-PAGE analyses of analytical SEC elution fractions monitoring the interaction of ASCC3^HR with selected TRIP4 variants. Equivalent elution fractions are vertically aligned. Molecular mass markers in kDa are shown on the left; protein bands are identified on the right. In the bottom panel, separate regions of the same gel were spliced together for display purposes (see Source Data file for uncropped gel). Dashed line, splice line. Experiments were repeated independently at least three times with similar results. c Overview of the cryoEM reconstruction of the ASCC3^HR-TRIP4 complex. Regions/domains of ASCC3^HR and TRIP4 are labeled. In this and the following panels: ASCC3^HR NC, dark gray; ASCC3^HR CC, light gray; NC-CC linker, black; TRIP4, red. Rotation symbol, orientation relative to the left panel. d Cartoon plot of the ASCC3^HR-TRIP4 complex model in the same orientations as in (c). Zn²⁺ ions, green spheres. e Close-up views of the interfaces of the ZnF domain (left), lasso-like peptide (middle) and ASCH domain (right) with ASCC3^HR. Interacting residues are shown as sticks, colored by atom type, and labeled. Carbon, as the respective protein region; nitrogen, blue; oxygen, light red. Dashed black lines, hydrogen bonds or salt bridges. Rotation symbols, orientations relative to (c, d), left panels. Source data are provided as a Source Data file.