Table 2 Cryo-EM data collection, refinement and validation statistics for SSU body

Magnification

×165,000

×270,000

×270,000

×270,000

×105,000

Acceleration voltage (kV)

300

300

300

300

300

Electron exposure (e⁻/Ų)

11

6

6

6

25

Defocus range (μm)

−0.4 to 1.6

−0.4 to −1.0

−0.4 to −1.0

−0.4 to −1.0

−0.4 to −1.6

Pixel size (Å)

0.53

0.45

0.45

0.45

0.51

Symmetry imposed

C1

C1

C1

C1

C1

Initial particle images (no.)

754,663

219,953

757,044

464,723

2,146,827

Final particle images (no.)

514,855

179,724

419,159

275,137

1,301,160

Map resolution (Å)

2.08

2.04

1.79

2.12

1.89

 FSC threshold

0.143

0.143

0.143

0.143

0.143

Initial model used (PDB code)

7K00

7K00

7K00

7K00

7K00

Model resolution (masked, Å)

2.1

2.0

1.8

2.1

1.9

 FSC threshold

0.5

0.5

0.5

0.5

0.5

CC (mask)

0.81

0.85

0.83

0.88

0.81

CC (volume)

0.80

0.84

0.81

0.87

0.81

Map sharpening B factor (Ų)

-32.2

−24.5

−53.9

−5.1

−36.6

 Nonhydrogen atoms

37,814

35,490

38,708

35,552

35,196

 Protein residues

1,552

1,279

1,523

1,272

1,266

 RNA residues

1,114

1,077

1,161

1,090

1,071

 Waters

1,416

1,933

1,616

1,928

1,869

 Magnesium (MG)

55

54

63

57

58

 Potassium (K)

29

25

25

28

24

 Antibiotics*

SCM, HY0 (3), 5I0

KSG, CA7 (5)

TAC, 5I0

AM2 (3)

LLL (4)

 Protein

82.43

53.52

59.68

55.00

60.73

 RNA

54.40

40.44

45.74

48.01

48.21

 Ligand

55.57

66.05

30.78

54.19

52.66

 Water

49.17

39.57

32.33

42.61

46.19

 Bond lengths (Å)

0.008

0.008

0.008

0.007

0.008

 Bond angles (°)

1.496

1.536

1.515

1.585

1.581

 MolProbity score

0.95

0.72

0.87

0.87

0.71

 Clashscore

0.59

0.43

0.37

0.93

0.38

 Poor rotamers (%)

0.86

0.66

0.40

0.10

0.38

 Favored (%)

96.22

97.68

96.41

97.58

97.65

 Allowed (%)

3.71

2.32

3.46

2.42

2.35

 Disallowed (%)

0.07

0.00

0.14

0.00

0.00

 Ramachandran Z score

−1.66

−0.88

−1.33

−0.51

−0.61