Extended Data Fig. 2: Cryo-EM data collection and processing.

a, Representative micrograph (graphene oxide coated grid, imaged using a Talos Arctica and a Gatan K3 camera) showing CUL1-SKP1-FBXL17-KEAP1^V98A particles. b, Resolution estimation using the FSC = 0.143 criterion⁵⁰ indicates an overall resolution of 8.5 Å for the cryo-EM reconstruction. c. Data processing scheme. Datasets were initially processed independently and then combined for the final refinement. EM volumes are shown in grey and orientation distributions are given for intermediate refinement steps. The final reconstruction is shown with and without sharpening applied, and additionally colored by local resolution (determined using RELION3). d, e, Initial model generation. We originally obtained an initial reference by generating a low-resolution volume with the overall shape of the complex observed in 2D class averages (d) and later also verified this solution using CRYOSPARC2 ab initio model generation (e; see Methods for details).