Extended Data Table 2.

Cryo-electron microscopy data collection, refinement and validation statistics

	S1+ACE2 Non-uniform Refinement (EMDB-11681) (PDB 7A91)	S1+ACE2 Unmasked Refinement (EMDB-11682) (PDB 7A92)	2 Erect RBD (EMDB-11683) (PDB 7A93)	1 ACE2 Bound Closed (EMDB-11684) (PDB 7A94)	1 ACE2 Bound 1 Erect RBD Clockwise (EMDB-11685) (PDB 7A95)	1 ACE2 Bound 1 Erect RBD Anticlockwise (EMDB-11686) (PDB 7A96)	2 ACE2 Bound (EMDB-11687) (PDB 7A97)	3ACE2 Bound (EMDB-11688) (PDB 7A98)
Data collection and processing
Voltage (kV)	300	300	300	300	300	300	300	300
Electron exposure (e-/Å2)	54.4	54.4	54.4	54.4	54.4	54.4	54.4	54.4
Defocus range (μm)	-1.5 to -3.0	-1.5 to -3.0	-1.5 to -3.0	-1.5 to -3.0	-1.5 to -3.0	-1.5 to -3.0	-1.5 to -3.0	-1.5 to -3.0
Pixel size (Å)	1.08	1.08	1.08	1.08	1.08	1.08	1.08	1.08
Symmetry imposed	Cl	Cl	Cl	Cl	Cl	Cl	Cl	C3
Final particle images (no.)	315 k	315 k	13 k	83 k	40 k	22 k	40 k	8k
Map resolution (Å)	3.6	4.2	5.9	3.9	4.3	4.8	4.4	5.4
FSC threshold = 0.143
Map resolution range (Å)	3-5	4-6	5-9	3.5 - 7.5	4-8	4-8	4-8	5-8
Refinement
Initial model used (PDB code)	6M0J	-	-	-	-	-	-	-
Model resolution (Å)	3.6	4.4	6.7	4.0	4.4	4.9	4.6	6.1
FSC threshold = 0.5
Map sharpening B factor (Å2)	-98.4	-158.9	-169.6	-75.0	-64.7	-66.1	-67.2	-119.6
Model composition
Non-hydrogen atoms	6915	10040	25243	30475	29904	29828	34645	39456
Protein residues	839	1231	3221	3825	3794	3783	4373	4962
Ligands	10	10	-	24	-	-	-	-
R.m.s. deviations
Bond lengths (Å)	0.006	0.007	0.004	0.007	0.004	0.004	0.004	0.004
Bond angles (°)	0.763	1.151	0.889	0.859	0.906	0.906	0.899	0.918
Validation
MolProbity score	1.46	1.55	1.62	1.57	1.71	1.75	1.81	1.85
Clashscore	3.25	3.71	2.83	3.38	3.48	3.88	4.85	5.71
Poor rotamers (%)	0.81	1.10	0.85	0.90	0.90	0.82	0.23	0.83
Ramachandran plot
Favored (%)	95.07	94.81	90.11	93.16	88.97	89.21	89.70	90.23
Allowed (%)	4.93	5.02	9.89	6.84	11.03	10.77	10.28	9.65
Disallowed (%)	0.00	0.16	0.00	0.00	0.00	0.03	0.02	0.12