2RF3

Crystal Structure of Tricyclo-DNA: An Unusual Compensatory Change of Two Adjacent Backbone Torsion Angles

Experimental procedure

Experimental method	SINGLE WAVELENGTH
Source type	SYNCHROTRON
Source details	NSLS BEAMLINE X29A
Synchrotron site	NSLS
Beamline	X29A
Temperature [K]	120
Detector technology	CCD
Collection date	2007-05-02
Detector	ADSC QUANTUM 315
Wavelength(s)	1.0809
Spacegroup name	P 32
Unit cell lengths	26.587, 26.587, 98.238
Unit cell angles	90.00, 90.00, 120.00

Refinement procedure

Resolution	32.740 - 1.750
R-factor	0.17829
Rwork	0.176
R-free	0.22495
Structure solution method	MOLECULAR REPLACEMENT
Starting model (for MR)	1ehv
RMSD bond length	0.007
RMSD bond angle	1.757
Data reduction software	HKL-2000
Data scaling software	HKL-2000
Phasing software	MOLREP
Refinement software	REFMAC (5.2.0005)

Data quality characteristics

	Overall	Outer shell
Low resolution limit [Å]	32.740	1.796
High resolution limit [Å]	1.750	1.750
Rmerge	0.049
Number of reflections	6884
<I/σ(I)>	23.2
Completeness [%]	88.0	60
Redundancy	3.6

Crystallization Conditions

crystal ID	method	pH	temperature	details
1	VAPOR DIFFUSION, HANGING DROP	7	291	0.75 mM of oligonucleotide, 20 mM sodium cacodylate, 6 mM NaCl, 40 mM KCl and 5% MPD against 0.7 mL of 35% MPD, pH 7.0, VAPOR DIFFUSION, HANGING DROP, temperature 291K
1	VAPOR DIFFUSION, HANGING DROP	7	291	0.75 mM of oligonucleotide, 20 mM sodium cacodylate, 6 mM NaCl, 40 mM KCl and 5% MPD against 0.7 mL of 35% MPD, pH 7.0, VAPOR DIFFUSION, HANGING DROP, temperature 291K

Crystallization Reagents

ID	crystal ID	solution ID	reagent name	concentration	details
1	1	1	sodium cacodylate
2	1	1	NaCl
3	1	1	KCl
4	1	1	MPD
5	1	2	sodium cacodylate
6	1	2	NaCl
7	1	2	KCl
8	1	2	MPD