a, Workflow for the apo non-engaged condensin arm segment. Particles of the tetramer complex were initially processed and preliminary angles and translations were assigned as described in Extended Data Fig. 1. b, Representative 2D classes (top), cryo-EM density map and its local resolution plot as calculated by RELION (left) and FSC curves (right) for the arm segment. c, Workflow for the apo bridged condensin arm segment. Particles of the pentamer bridged class were initially processed and preliminary angles and translations were assigned as described in Extended Data Fig. 1. d, Representative 2D classes (top), 7.8 Å cryo-EM density map and its local resolution plot as calculated by RELION (left) and FSC curves (right) for the arm segment.