Table 1. X-ray Crystallography Data Collection and Refinement Statistics.

data collection
space group	C 2 2 21
resolution range	67.71–2.09 (2.17–2.09)
cell dimensions
a, b, c (Å)	76.83, 143.24, 133.64
α, β, γ (deg)	90, 90, 90
R-merge	0.083 (0.730)
I/ σ (I)	15.98 (2.50)
CC1/2	0.99 (0.80)
CC*	1 (0.94)
CC work/CC free	0.95(0.87)/0.88 (0.78)
completeness (%)	99.89 (99.93)
multiplicity	6.8 (6.7)
refinement
no. unique reflections	43945 (4321)
Rwork/Rfree (%)	0.1993 (0.2550)/0.2308 (0.2886)
RMS deviations
bond lengths (Å)	0.007
bond angles (deg)	0.97
average B-factor all atoms (Å2)	40.78
Ramachandran plot of all protein residues
favored (%)	97.64
allowed (%)	2.36
number of residues
RNA	65
protein residues	430