3Q51

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

Experimental procedure

Experimental method	SINGLE WAVELENGTH
Source type	SYNCHROTRON
Source details	SSRL BEAMLINE BL9-2
Synchrotron site	SSRL
Beamline	BL9-2
Temperature [K]	100
Detector technology	CCD
Collection date	2010-04-16
Detector	MARMOSAIC 325 mm CCD
Wavelength(s)	0.98
Spacegroup name	P 63 2 2
Unit cell lengths	116.558, 116.558, 57.926
Unit cell angles	90.00, 90.00, 120.00

Refinement procedure

Resolution	27.840 - 2.850
R-factor	0.2306
Rwork	0.226
R-free	0.27220
Structure solution method	FOURIER SYNTHESIS
Starting model (for MR)	3gca
RMSD bond length	0.006
RMSD bond angle	0.844
Data reduction software	HKL-2000
Data scaling software	SCALEPACK
Phasing software	PHENIX (1.6.4_486)
Refinement software	PHENIX (1.6.4_486)

Data quality characteristics

	Overall	Inner shell	Outer shell
Low resolution limit [Å]	50.000	50.000	2.950
High resolution limit [Å]	2.850	6.140	2.850
Rmerge	0.075	0.056	0.357
Number of reflections	5771
<I/σ(I)>	14.8
Completeness [%]	99.2	94.4	100
Redundancy	7.2	5.6	8.4

Crystallization Conditions

crystal 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