1EN8

1 A 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	IMAGE PLATE
Collection date	1998-11-19
Detector	MARRESEARCH
Spacegroup name	C 1 2 1
Unit cell lengths	31.847, 25.100, 34.144
Unit cell angles	90.00, 114.87, 90.00

Refinement procedure

Resolution	8.000 - 0.985
Rwork	0.118
R-free	0.14050
Structure solution method	MOLECULAR REPLACEMENT
Starting model (for MR)	BDJ019
RMSD bond length	0.019 *
RMSD bond angle	2.910 *
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	0.044	0.104
Total number of observations	75660 *
Number of reflections	13619
<I/σ(I)>	25	9.1
Completeness [%]	97.5	94.9
Redundancy	5.56

Crystallization Conditions

crystal ID	method	pH	temperature	details
1	VAPOR DIFFUSION, SITTING DROP		4 *	initial concentration in droplet: 0.24 mM dna, 8.57 mM calcium acetate, 0.11 mM streptonigrin, 10-15% MPD, 45% 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	calcium 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	0.24 (mM)
2	1	drop	divalent cation	8.57 (mM)
3	1	drop	streptonigrin	0.11 (mM)
4	1	reservoir		45 (%)
5	1	drop	spermine-HCl	0.24 (mM)