Experiment: 1N1O

Crystal Structure of a B-form DNA Duplex Containing (L)-alpha-threofuranosyl (3'-2') Nucleosides: A Four-Carbon Sugar is Easily Accommodated into the Backbone of DNA

X-RAY DIFFRACTION

Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
experimental model	Other		B-form DNA (native Dickerson-Drew dodecamer)

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, SITTING DROP	7	298	oligonucleotide, sodium cacodylate, magnesium acetate, spermine tetrahydrochloride, 2-methyl-2,4-pentanediol (MPD), pH 7, VAPOR DIFFUSION, SITTING DROP, temperature 298K

Crystal Properties
Matthews coefficient	Solvent content
1.75	29.04

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 25.277	α = 90
b = 40.08	β = 90
c = 65.86	γ = 90

Symmetry
Space Group	P 21 21 21

Diffraction

Diffraction Experiment
ID #	Crystal ID	Scattering Type	Data Collection Temperature	Detector	Detector Type	Details	Collection Date	Monochromator	Protocol
1	1	x-ray	120	CCD	MARRESEARCH		2001-02-20	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	APS BEAMLINE 5ID-B	0.978	APS	5ID-B

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	R Merge I (Observed)	Net I Over Average Sigma (I)	Redundancy	Number Reflections (All)	Number Reflections (Observed)	Observed Criterion Sigma (F)	Observed Criterion Sigma (I)	B (Isotropic) From Wilson Plot
1	1.2	20	99.2	0.037			21360	21311	2	1

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	R Merge I (Observed)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
	1.2	1.24	98.2		0.327

Refinement

Statistics
Diffraction ID	Structure Solution Method	Starting model	Resolution (High)	Resolution (Low)	Number Reflections (All)	Number Reflections (Observed)	Number Reflections (R-Free)	Percent Reflections (Observed)	R-Work (Depositor)	R-Work (DCC)	R-Free (Depositor)	R-Free (DCC)	R-Free Selection Details	Mean Isotropic B
X-RAY DIFFRACTION	MOLECULAR REPLACEMENT	B-form DNA (native Dickerson-Drew dodecamer)	1.2	20	21311	21311			0.16	0.1614		0.1684	random

Temperature Factor Modeling
Anisotropic B[1][1]	Anisotropic B[1][2]	Anisotropic B[1][3]	Anisotropic B[2][2]	Anisotropic B[2][3]	Anisotropic B[3][3]

RMS Deviations
Key	Refinement Restraint Deviation
s_angle_d	0.014
s_bond_d	0.007

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms
Nucleic Acid Atoms	484
Solvent Atoms	197
Heterogen Atoms	1

Software

Software
Software Name	Purpose
SHELXL-97	refinement
SCALEPACK	data scaling
CNS	refinement
MAR345	data collection
CNS	phasing