Tilt series were collected on a Talos Arctica (200kV) microscope with a K3 direct electron detector and a Bioquantum energy filter (slit width=20 eV; Gatan). Tomograms were reconstructed using weighed back-projection in IMOD4.11.Particles were manually picked in EMAN2 (version 2.91) using 2spt_boxer_old.py. 2,561 particles were extracted from 101 tomograms with a box size of 256 pixels and a final pixel size of 3.48 Å/pixel.
