1EN9

1A CRYSTAL STRUCTURES OF B-DNA REVEAL SEQUENCE-SPECIFIC BINDING AND GROOVE-SPECIFIC BENDING OF DNA BY MAGNESIUM AND CALCIUM.

Experimental procedure

Experimental method	SINGLE WAVELENGTH
Source type	SYNCHROTRON
Source details	NSLS BEAMLINE X8C
Synchrotron site	NSLS
Beamline	X8C
Temperature [K]	100
Detector technology	AREA DETECTOR
Collection date	1998-11-19
Detector	MARRESEARCH
Spacegroup name	C 1 2 1
Unit cell lengths	32.243, 25.352, 34.190
Unit cell angles	90.00, 117.17, 90.00

Refinement procedure

Resolution	8.000 - 0.985
R-factor	0.1405
Rwork	0.141
R-free	0.15090
Structure solution method	MOLECULAR REPLACEMENT
Starting model (for MR)	BDJ019
RMSD bond length	0.018
RMSD bond angle	3.610 *
Data reduction software	DENZO
Data scaling software	SCALEPACK
Phasing software	X-PLOR
Refinement software	SHELXL-97

Data quality characteristics

	Overall	Outer shell
Low resolution limit [Å]	8.000	1.016
High resolution limit [Å]	0.985	0.985
Rmerge	0.031	0.122
Total number of observations	63745 *
Number of reflections	13087
<I/σ(I)>	32.8	6.9
Completeness [%]	93.3	89.5
Redundancy	4.87

Crystallization Conditions

crystal ID	method	pH	temperature	details
1	VAPOR DIFFUSION, SITTING DROP		4 *	initial concentration in droplet: 0.17 mM dna, 31.40 mM magnesium acetate 0.28 mM streptonigrin, 10-15% MPD, 30% final MPD concentration in reservoir. Solutions were unbuffered, VAPOR DIFFUSION, SITTING DROP, temperature 275.0K

Crystallization Reagents

ID	crystal ID	solution ID	reagent name	concentration	details
1	1	1	magnesium acetate
2	1	1	streptonigrin
3	1	1	MPD
4	1	2	MPD

Crystallization Reagents in Literatures

ID	crystal ID	solution	reagent name	concentration (unit)	details
1	1	drop	duplex DNA	0.17 (mM)
2	1	drop	divalent cation	31.40 (mM)
3	1	drop	streptonigrin	0.28 (mM)