1KGK

Direct Observation of a Cytosine Analog that Forms Five Hydrogen Bonds to Guanosine; Guanyl G-Clamp

X-RAY DIFFRACTION

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	Hanging Drop	6	298	1.2 mM DNA, 5% MPD, 20 mM Sodium Cacodylate, 40 mM sodium chloride, 6 mM potassium chloride, 10 mM magnesium chloride; equilibrated against 35% MPD, pH 6.0, Hanging Drop, temperature 298K

Crystal Properties
Matthews coefficient	Solvent content
1.84	33.07

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 24.52	α = 90
b = 43.02	β = 90
c = 46.68	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	mirrors	2000-04-29	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	10	99.6	0.047			27320	27320

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
	1	1.1	99.6

Refinement

Statistics
Diffraction ID	Structure Solution Method	Resolution (High)	Resolution (Low)	Number Reflections (All)	Number Reflections (Observed)	Number Reflections (R-Free)	Percent Reflections (Observed)	R-Factor (All)	R-Work	R-Free	Mean Isotropic B
X-RAY DIFFRACTION	MOLECULAR REPLACEMENT	1	10	27320	27320		99.6	0.128

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]

Coordinate Error
Structure Solution Method	Refinement High Resolution	Refinement Low Resolution
	283.5	608

RMS Deviations
Key	Refinement Restraint Deviation
s_from_restr_planes	0.222
s_non_zero_chiral_vol	0.055
s_angle_d	0.021
s_bond_d	0.015
s_zero_chiral_vol

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms
Nucleic Acid Atoms	686
Solvent Atoms	155
Heterogen Atoms	68

Software

Software
Software Name	Purpose
AMoRE	phasing
SHELXL-97	refinement
DENZO	data reduction
SCALEPACK	data scaling

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM157729.