KEY RESOURCES TABLE

REAGENT or RESOURCE	SOURCE	IDENTIFIER
Chemicals, Peptides, and Recombinant Proteins
Rabbit muscle aldolase	Sigma Aldrich	89933139
Deposited Data
Raw, electron micrographs, T20S proteasome	Campbell et al. 2015	EMPIAR-10025
Raw, electron micrographs, HA Trimer	Noble et al. 2018	EMPIAR-10175
Raw, electron micrographs aldolase	This paper	EMPIAR-10379
Cryo-EM map of T20S proteasome (Figure 4D)	This paper	EMD-21491
Cryo-EM map of HA Trimer (Figure 5D)	This paper	EMD-21490
Cryo-EM map of aldolase (Figure 6D)	This paper	EMD-21492
Software and Algorithms
Python	Anaconda	https://www.anaconda.com/distribution
Leginon	Suloway et al., 2005	https://emg.nysbc.org/redmine/projects/leginon
Appion	Lander et al., 2009	https://emg.nysbc.org/redmine/projects/appion
CTFFIND4	Rohou and Grigorieff, 2015	http://grigoriefflab.janelia.org/ctffind4
MotionCor2	Zheng et al., 2017	https://emcore.ucsf.edu/ucsf-motioncor2
RELION3	Zivanov et al., 2018	https://www3.mrc-lmb.cam.ac.uk/relion
UCSF Chimera	Goddard et al., 2007	https://www.cgl.ucsf.edu/chimera
cryoSPARC	Punjani et al., 2017	https://cryosparc.com
Tensorflow	Abadi et al. 2016	https://www.tensorflow.org
Other
Vitrobot Mark IV	Thermo Fisher Scientific