8Q50

Nitrogenase Fe protein from Methanothermococcus thermolithotrophicus, tetragonal crystalline form at 1.91-A resolution

X-RAY DIFFRACTION

Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
experimental model	PDB	2NIP	NITROGENASE IRON PROTEIN FROM AZOTOBACTER VINELANDII

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, SITTING DROP	4.6	293.15	The purified protein was crystallised at a final concentration of 6 mg/ml by spotting 0.5 ul of crystallisation solution with 0.5 ul of protein sample. Crystallization was done anaerobically in a Coy tent containing N2/H2 (97:3%) atmosphere. The screening was done at 20 degrees Celsius on 96-Well MRC 2-drop polystyrene (SWISSCI) plates containing 90 ul of crystallization solution. The crystallisation solution in which crystals were obtained contained 30 % v/v 2-methyl-2,4-pentanediol, 100 mM sodium acetate, pH 4.6 and 20 mM calcium chloride.

Crystal Properties
Matthews coefficient	Solvent content
2.39	48.55

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 98.895	α = 90
b = 98.895	β = 90
c = 61.149	γ = 90

Symmetry
Space Group	P 43 21 2

Diffraction

Diffraction Experiment
ID #	Crystal ID	Scattering Type	Data Collection Temperature	Detector	Detector Type	Details	Collection Date	Monochromator	Protocol
1	1	x-ray	100	PIXEL	DECTRIS EIGER X 16M		2019-11-22	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	SOLEIL BEAMLINE PROXIMA 1	1.74013	SOLEIL	PROXIMA 1

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	R Merge I (Observed)	Rrim I (All)	Rpim I (All)	CC (Half)	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	1.91	52.01	100	0.159	0.161	0.025	0.997	15.9	41.2		24200

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	R Merge I (Observed)	Rrim I (All)	Rpim I (All)	CC (Half)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
1	1.91	1.94	100		3.12	3.19	0.644	0.616	1.4	23.9

Refinement

Statistics
Diffraction ID	Structure Solution Method	Cross Validation method	Resolution (High)	Resolution (Low)	Cut-off Sigma (F)	Number Reflections (Observed)	Number Reflections (R-Free)	Percent Reflections (Observed)	R-Factor (Observed)	R-Work	R-Free	Mean Isotropic B
X-RAY DIFFRACTION	MOLECULAR REPLACEMENT	FREE R-VALUE	1.91	52.01	1.35	24197	1157	99.98	0.2032	0.2019	0.2305	46.31

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
f_dihedral_angle_d	19.331
f_angle_d	1.431
f_chiral_restr	0.305
f_bond_d	0.013
f_plane_restr	0.012

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	2123
Nucleic Acid Atoms
Solvent Atoms	126
Heterogen Atoms	29

Software

Software
Software Name	Purpose
PHENIX	refinement
autoPROC	data reduction
autoPROC	data scaling
PHASER	phasing

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 R01GM133198.