3Q51

Structural analysis of a class I PreQ1 riboswitch aptamer in the metabolite-free state.

X-RAY DIFFRACTION

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, HANGING DROP	6	295	1.5 M Li2SO4, 0.2 M MES pH 6.0, 0.02 M Magnesium sulfate, and 0.002 M spermine-HCl, VAPOR DIFFUSION, HANGING DROP, temperature 295K

Crystal Properties
Matthews coefficient	Solvent content
5.358	77.044

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 116.558	α = 90
b = 116.558	β = 90
c = 57.926	γ = 120

Symmetry
Space Group	P 63 2 2

Diffraction

Diffraction Experiment
ID #	Crystal ID	Scattering Type	Data Collection Temperature	Detector	Detector Type	Details	Collection Date	Monochromator	Protocol
1	1	x-ray	100	CCD	MARMOSAIC 325 mm CCD	Rh coated flat mirror, toroidal focusing mirror	2010-04-16	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	SSRL BEAMLINE BL9-2	0.98	SSRL	BL9-2

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	R Merge I (Observed)	Net I Over Average Sigma (I)	Redundancy	Number Reflections (All)	Number Reflections (Observed)	Observed Criterion Sigma (F)	Observed Criterion Sigma (I)	B (Isotropic) From Wilson Plot
1	2.85	50	99.2	0.075	14.8	7.2		5771		-3	70.4

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	R Merge I (Observed)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
1	2.85	2.95	100		0.357		8.4	558

Refinement

Statistics
Diffraction ID	Structure Solution Method	Cross Validation method	Starting model	Resolution (High)	Resolution (Low)	Number Reflections (Observed)	Number Reflections (R-Free)	Percent Reflections (Observed)	R-Factor (Observed)	R-Work	R-Free	R-Free Selection Details	Mean Isotropic B
X-RAY DIFFRACTION	FOURIER SYNTHESIS	THROUGHOUT	3GCA	2.85	27.84	5639	561	97.58	0.2306	0.226	0.2722	copied R-free set from 3GCA	56.6848

Temperature Factor Modeling
Anisotropic B[1][1]	Anisotropic B[1][2]	Anisotropic B[1][3]	Anisotropic B[2][2]	Anisotropic B[2][3]	Anisotropic B[3][3]
10.6047			10.6047		-21.2094

RMS Deviations
Key	Refinement Restraint Deviation
f_dihedral_angle_d	19.382
f_angle_d	0.844
f_chiral_restr	0.056
f_plane_restr	0.008
f_bond_d	0.006

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms
Nucleic Acid Atoms	680
Solvent Atoms	4
Heterogen Atoms	6

Software

Software
Software Name	Purpose
SCALEPACK	data scaling
PHENIX	refinement
PDB_EXTRACT	data extraction
HKL-2000	data collection
HKL-2000	data reduction
HKL-2000	data scaling
PHENIX	phasing

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM133198.