1EN3

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	IMAGE PLATE
Collection date	1998-11-19
Detector	MARRESEARCH
Spacegroup name	C 1 2 1
Unit cell lengths	32.001, 25.369, 33.633
Unit cell angles	90.00, 112.98, 90.00

Refinement procedure

Resolution	8.000 - 0.985
R-factor	0.1409
Rwork	0.141
R-free	0.15920
Structure solution method	MOLECULAR REPLACEMENT
Starting model (for MR)	BDJ019
RMSD bond length	0.033 *
RMSD bond angle	2.980 *
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	0.047	0.123
Total number of observations	77354 *
Number of reflections	13464
<I/σ(I)>	21.6	7.4
Completeness [%]	95.0	90.7
Redundancy	5.75

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 MAGNESIUM 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	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	0.24 (mM)
2	1	drop	divalent cation	8.57 (mM)
3	1	drop	streptonigrin	0.11 (mM)
4	1	reservoir		45 (%)