Cryo-EM data collection, refinement and validation statistics

	zfOtop1 in nanodiscs (EMDB 9360, PDB 6NF4)	chOtop3 in nanodiscs (EMDB 9361, PDB 6NF6)
Data collection and processing
Magnification	29,000	29,000
Voltage (kV)	300	300
Electron exposure (e−/Å2)	50	50
Defocus range (μm)	0.6–1.8	0.6–1.8
Pixel size (Å)	1.03	1.03
Symmetry imposed	C2	C2
Initial particle images (no.)	1,517,125	1,386,058
Final particle images (no.)	67,425	43,667
Map resolution (Å)	2.98	3.32
FSC threshold	0.143	0.143
Map resolution range (Å)
Refinement
Initial model used (PDB code)	N/A	6NF4
Model resolution (Å)	3.06	3.35
FSC threshold	0.5	0.5
Model resolution range (Å)	2.9–8	3.3–8
Map sharpening B factor (Å2)	−74	−50
Model composition
Nonhydrogen atoms	6,970	6,600
Protein residues	842	822
Ligands	8	2
B factors (Å2)
Protein	24.8	53.8
Ligand	71.8	49.2
R.m.s. deviations
Bond lengths (Å)	0.01	0.02
Bond angles (°)	1.00	0.95
Validation
MolProbity score	1.00	1.56
Clashscore	1.08	4.54
Poor rotamers (%)	0.27	0
Ramachandran plot
Favored (%)	96.8	95.2
Allowed (%)	3.2	4.5
Disallowed (%)	0	0.3