Experiment: 3TQ2

Merohedral twinning in protein crystals revealed a new synthetic three helix bundle motif

X-RAY DIFFRACTION

Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
in silico model	Other		35-residue polyalanine model

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, HANGING DROP	7.5	298	0.1M Hepes pH 7.5, 1.8-2.5M ammonium sulfate, 1.5-3% w/v PEG400, VAPOR DIFFUSION, HANGING DROP, temperature 298K

Crystal Properties
Matthews coefficient	Solvent content
1.85	33.42

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 22.365	α = 90
b = 22.365	β = 90
c = 51.007	γ = 120

Symmetry
Space Group	P 3

Diffraction

Diffraction Experiment
ID #	Crystal ID	Scattering Type	Data Collection Temperature	Detector	Detector Type	Details	Collection Date	Monochromator	Protocol
1	1	x-ray	100	CCD	MAR CCD 165 mm		2008-07-19	M	SINGLE WAVELENGTH
2	1	x-ray		CCD	Nonius Kappa CCD		2008-05-08	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	ELETTRA BEAMLINE 5.2R	1.00	ELETTRA	5.2R
2	ROTATING ANODE	OTHER	1.54

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
1,2	1.1	50	95	0.081			10855	30622	2	2

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	1.1	1.14	85.4		0.353	1.74

Refinement

Statistics
Diffraction ID	Structure Solution Method	Starting model	Resolution (High)	Resolution (Low)	Cut-off Sigma (F)	Number Reflections (All)	Number Reflections (Observed)	Number Reflections (R-Free)	Percent Reflections (Observed)	R-Factor (All)	R-Factor (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	a 35 Poly-Ala model	1.1	50	2	10855	30622	543		0.21	0.188	0.158	0.1649	0.185	0.1819	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
r_angle_refined_deg	0.032
r_bond_refined_d	0.017

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	279
Nucleic Acid Atoms
Solvent Atoms	28
Heterogen Atoms	3

Software

Software
Software Name	Purpose
HKL-2000	data collection
AMoRE	phasing
REFMAC	refinement
HKL-2000	data reduction
SCALA	data scaling