2NIP

NITROGENASE IRON PROTEIN FROM AZOTOBACTER VINELANDII

X-RAY DIFFRACTION

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Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
experimental model	PDB	1NIP	PDB ENTRY 1NIP

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	liquid-liquid diffusion	8		PROTEIN WAS CRYSTALLIZED BY LIQUID-LIQUID DIFFUSION METHOD, USING 25-30% PEG 4000, 140-200 MM NA2MOO4, 100 MM TRIS-CL, PH 8.0; PROTEIN WAS HELD IN A BUFFER OF 20% GLYCEROL, 50 MM TRIS-CL, PH 8.0, 450 MM NACL, AND 2 MM NA2S2O4 PRIOR TO CRYSTALLIZATION., liquid-liquid diffusion

Crystal Properties
Matthews coefficient	Solvent content
2.4	47

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 73.12	α = 90
b = 90.53	β = 90
c = 91.21	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	113	IMAGE PLATE	MARRESEARCH	MIRROR	1995-03-16	M

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	SSRL BEAMLINE BL7-1		SSRL	BL7-1

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	R Merge I (Observed)	R Sym 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	2.13	50	92.9	0.085	0.085	6.9	4		29060			35

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	R Merge I (Observed)	R-Sym I (Observed)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
	2.2	2.28	94.9		0.309	0.309	2.4	3.8

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 1NIP	2.2	50	29180	1737	92.9	0.223	0.223	0.29	RANDOM	31.7

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]
-19.79			-4.98		-11.26

RMS Deviations
Key	Refinement Restraint Deviation
x_dihedral_angle_d	23.9
x_scangle_it	5.18
x_mcangle_it	3.64
x_scbond_it	3.62
x_mcbond_it	2.4
x_angle_deg	1.9
x_improper_angle_d	1.64
x_bond_d	0.017
x_bond_d_na
x_bond_d_prot
x_angle_d
x_angle_d_na
x_angle_d_prot
x_angle_deg_na
x_angle_deg_prot
x_dihedral_angle_d_na
x_dihedral_angle_d_prot
x_improper_angle_d_na
x_improper_angle_d_prot

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	4356
Nucleic Acid Atoms
Solvent Atoms	376
Heterogen Atoms	8

Software

Software
Software Name	Purpose
AMoRE	phasing
X-PLOR	refinement
DENZO	data reduction
SCALEPACK	data scaling