3N4O

Insights into the stabilizing contributions of a bicyclic cytosine analogue: crystal structures of DNA duplexes containing 7,8-dihydropyrido[2,3-d]pyrimidin-2-one

Experimental procedure

Experimental method	SINGLE WAVELENGTH
Source type	SYNCHROTRON
Source details	PHOTON FACTORY BEAMLINE BL-6A
Synchrotron site	Photon Factory
Beamline	BL-6A
Temperature [K]	100
Detector technology	CCD
Collection date	2008-01-26
Detector	ADSC QUANTUM 4
Wavelength(s)	0.978
Spacegroup name	P 21 21 21
Unit cell lengths	25.030, 41.659, 64.569
Unit cell angles	90.00, 90.00, 90.00

Refinement procedure

Resolution	9.890 - 2.900
R-factor	0.254
Rwork	0.232
R-free	0.29700
Structure solution method	MOLECULAR REPLACEMENT
Starting model (for MR)	1dnh
RMSD bond length	0.009
RMSD bond angle	1.100
Data reduction software	HKL-2000
Data scaling software	HKL-2000
Phasing software	AMoRE
Refinement software	CNS (1.2)

Data quality characteristics

	Overall	Outer shell
Low resolution limit [Å]	50.000	3.000
High resolution limit [Å]	2.900	2.900
Rmerge	0.035	0.298
Number of reflections	1714
<I/σ(I)>	69.6	10.8
Completeness [%]	99.8	100
Redundancy	13.1	13.5

Crystallization Conditions

crystal ID	method	pH	temperature	details
1	VAPOR DIFFUSION, HANGING DROP	6	277	0.60mM ssDNA, 20mM Sodium cacodylate (pH6.0), 6mM Spermine tetrahydrochloride, 40mM Potassium chloride, 6mM Sodium chloride, 0.2% CHAPS, 0.30mM Hoechst33258, 5% MPD , VAPOR DIFFUSION, HANGING DROP, temperature 277K