Table 1.

Data Collection and Refinement Statistics.

Data collection and processing
Magnification	105,000
Voltage (kV)	300
Total dose (e–/Å2)	51.99
Dose per physical pixel per second	27.22
Dose per Å2 per second	39.993
Exposure time (s)	1.3
Number of frames	50
Dose per frame (e/Å2)	1.04
Defocus range (μm)	−1.0 to −2.2
Pixel size (Å)	0.825
Symmetry	C1
Initial particle images	1822048
Final particle images	178031
Map resolution (Å) FSC	3.3
Threshold	(0.143)
Refinement
Model composition
Non-hydrogen atoms	7222
Protein residues	933
Ligands	13
B-factors (Å2)
Protein	56.68
Ligands	68.31
R.m.s deviations
Bond lengths (Å)	.003
Bond angles (°)	1.036
Validation
MolProbity score	2.06
Clashscore	12.85
Rotamer outliers (%)	0
Ramachandran plot
Favored (%)	93.07
Allowed (%)	6.72
Disallowed (%)	0.22