4AEA

Dimeric alpha-cobratoxin X-ray structure: Localization of intermolecular disulfides and possible mode of binding to nicotinic acetylcholine receptors

X-RAY DIFFRACTION

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Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1		2		60% (V/V) 2-METHYL-2,4- PENTANEDIOL, 0.1 M GLYCINE-HCL PH 2

Crystal Properties
Matthews coefficient	Solvent content
2.48	50.44

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 86	α = 90
b = 86	β = 90
c = 37.12	γ = 120

Symmetry
Space Group	P 31 2 1

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	ADSC CCD		2008-03-15	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	ESRF BEAMLINE ID14-1		ESRF	ID14-1

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	1.94	37.24	99.8	0.08	17.9	7.7		11890		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	1.94	2.05	98.7		0.88	2.1	6.7

Refinement

Statistics
Diffraction ID	Structure Solution Method	Cross Validation method	Starting model	Resolution (High)	Resolution (Low)	Number Reflections (Observed)	Number Reflections (R-Free)	Percent Reflections (Observed)	R-Factor (Observed)	R-Work	R-Free	R-Free Selection Details	Mean Isotropic B
X-RAY DIFFRACTION	MOLECULAR REPLACEMENT	THROUGHOUT	PDB ENTRY 2CTX	1.94	37.24	11282	594	100	0.22037	0.21874	0.25142	RANDOM	33.338

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]
-0.55	-0.27		-0.55		0.82

RMS Deviations
Key	Refinement Restraint Deviation
r_dihedral_angle_2_deg	28.182
r_dihedral_angle_3_deg	12.751
r_dihedral_angle_4_deg	9.027
r_dihedral_angle_1_deg	6.025
r_scangle_it	1.226
r_angle_refined_deg	1.054
r_mcangle_it	0.799
r_scbond_it	0.746
r_mcbond_it	0.434
r_chiral_restr	0.066
r_bond_refined_d	0.006
r_gen_planes_refined	0.004
r_bond_other_d
r_angle_other_deg
r_gen_planes_other
r_nbd_refined
r_nbd_other
r_nbtor_refined
r_nbtor_other
r_xyhbond_nbd_refined
r_xyhbond_nbd_other
r_metal_ion_refined
r_metal_ion_other
r_symmetry_vdw_refined
r_symmetry_vdw_other
r_symmetry_hbond_refined
r_symmetry_hbond_other
r_symmetry_metal_ion_refined
r_symmetry_metal_ion_other
r_mcbond_other
r_mcangle_other
r_scbond_other
r_scangle_other
r_long_range_B_refined
r_long_range_B_other
r_rigid_bond_restr
r_sphericity_free
r_sphericity_bonded

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	1004
Nucleic Acid Atoms
Solvent Atoms	69
Heterogen Atoms	13

Software

Software
Software Name	Purpose
REFMAC	refinement
XDS	data reduction
SCALA	data scaling
PHASER	phasing