7TPO

Selenium-incorporated nitrogenase Fe-protein (Av2-Se) from A. vinelandii (1 mM KSeCN)

X-RAY DIFFRACTION

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, SITTING DROP	7.5	298	36-41% PEG400, 0.1-0.3 M sodium chloride, 0.1 M HEPES, pH 7.5, 2.5 mM dithionite, 0.17 mM Cymal-7

Crystal Properties
Matthews coefficient	Solvent content
2.04	39.78

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 45.883	α = 90
b = 74.757	β = 90
c = 75.144	γ = 90

Symmetry
Space Group	P 2 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	100	PIXEL	DECTRIS PILATUS 6M		2021-05-18	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	SSRL BEAMLINE BL12-2	0.97869, 0.98062	SSRL	BL12-2

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	1.35	45.85	99.3	0.161	0.173	0.064	0.987	9	13.2		57097			14.47

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	1.35	1.37	98.8		0.89	0.978	0.396	0.902		11.2

Refinement

Statistics
Diffraction ID	Structure Solution Method	Cross Validation method	Starting model	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	THROUGHOUT	PDB entry 6N4L	1.35	39.16	1.35	56934	5301	99.1	0.18	0.179	0.203	21.04

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]

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	2062
Nucleic Acid Atoms
Solvent Atoms	210
Heterogen Atoms	36

Software

Software
Software Name	Purpose
PHENIX	refinement
Aimless	data scaling
MOLREP	phasing
PDB_EXTRACT	data extraction
XDS	data reduction

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.