Extended Data Fig. 3 | Focused classif ication, ref inement and model
building: focus on the PARP2–HPF1 complex. a, The overall data set,
comprising 934,000 particles, was extensively classified with focus on PARP2–
HPF1 complex found in between the two nucleosomes. b, Cryo-EM map of
PARP2–HPF1 bound to the nucleosome in the activated conformation. Cryo-EM
map of this conformation was refined to 4.2 Å. FSC curve showing the
resolution of the map is below. c, Cryo-EM map of PARP2–HPF1 bound to the
nucleosome in open state 1. Cryo-EM map of this conformation was refined to
6.7 Å. FSC curve showing the resolution of the map is below. The map is
coloured by local resolution. d, Cryo-EM map of PARP2–HPF1 bound to the
nucleosome in open state 2. Cryo-EM map of this conformation was refined to
6.3 Å. FSC curve showing the resolution of the map is shown below. The map is
coloured by local resolution. e, The PARP2–HPF1 subset comprising 32,000
particles (left) was further classified and refined. Protruding DNA was
eliminated from refinements to improve the resolution. Final map (middle) was
refined to 3.9 Å. FSC curve is shown on the right. The map is coloured by local
resolution. f, Angular distribution for PARP2–HPF1. g, Directional FSC plot
showing reasonably uniform resolution in all directions. h, The models of the
PARP2 WGR domain (PDB 6F5B), PARP2 catalytic domain (CAT) with HD domain
(PDB 4T V J) and PARP2 catalytic domain without HD domain in complex with
HPF1 (PDB 6T X3) were refined into the cryo-EM map. The representative
regions showing map quality and fit of the model are shown. Side chains are
visible in most regions of the map.