3HR3

Interplay of Structure, Hydration and Thermal Stability in Formacetal Modified Oligonucleotides: RNA May Tolerate Hydrophobic Modifications Better than DNA

Experimental procedure

Experimental method	SINGLE WAVELENGTH
Source type	SYNCHROTRON
Source details	NSLS BEAMLINE X25
Synchrotron site	NSLS
Beamline	X25
Temperature [K]	110
Detector technology	CCD
Collection date	2009-01-20
Detector	ADSC QUANTUM 315r
Wavelength(s)	0.9795
Spacegroup name	P 41 21 2
Unit cell lengths	33.199, 33.199, 68.508
Unit cell angles	90.00, 90.00, 90.00

Refinement procedure

Resolution	29.880 - 1.750
R-factor	0.23147
Rwork	0.228
R-free	0.28185
Structure solution method	MOLECULAR REPLACEMENT
Starting model (for MR)	Single strand from the duplex of PDB ID 411D.
RMSD bond length	0.022
RMSD bond angle	3.037
Data reduction software	HKL-2000
Data scaling software	HKL-2000
Phasing software	MOLREP
Refinement software	REFMAC (5.5.0088)

Data quality characteristics

	Overall	Outer shell
Low resolution limit [Å]	50.000	1.780
High resolution limit [Å]	1.750	1.750
Rmerge	0.058	0.187
Number of reflections	4006
<I/σ(I)>	18.7
Completeness [%]	95.2	72.4
Redundancy	17	5.8

Crystallization Conditions

crystal ID	method	pH	temperature	details
1	VAPOR DIFFUSION, HANGING DROP	6	291	Sodium cacodylate (20 mM, pH 6.0), potassium chloride (40 mM), magnesium chloride (10 mM), spermine tetrahydrochloride (6 mM), and 2-methyl-2,4-pentanediol (MPD 5% v/v) , VAPOR DIFFUSION, HANGING DROP, temperature 291K