Fig. 1
Cryo-EM structure determination of the ATP-γ-S-bound human proteasome. a A typical cryo-EM micrograph of the ATP-γ-S-bound human proteasome imaged with a Tecnai Arctica microscope equipped with a Gatan K2 Summit direct detector camera. Scale bar, 100 nm. b Typical reference-free 2D class averages computed using the ROME software35. c–f Two different views of the cryo-EM density maps in the SA (panel c), SD1 (panel d), SD2 (panel e), and SD3 (panel f) states, colored according to subunit. g The 3.5-Å cryo-EM density of the CP in the combined SD state superimposed over its atomic model. Left, a lateral perspective. Right, a central slice. h Typical high-resolution densities of the secondary structures in the cryo-EM structure of the CP in the open-gate SD state
