7T4H

Selenium-incorporated nitrogenase Fe protein (Av2-Se) from A. vinelandii (22 mM KSeCN, with Av1)

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
2.03	39.42

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 45.82	α = 90
b = 74.754	β = 90
c = 74.801	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		2020-02-12	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	1.51	45.79	99.6	0.067	0.072	0.028	0.999	16.5	6.5	41124	40990			15.49

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	1.51	1.53	98.6		0.839	0.919	0.366	0.842	1.8	6

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	1.51	37.38	1.34	77370	3718	99.2	0.169	0.167	0.191	22.77

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	2057
Nucleic Acid Atoms
Solvent Atoms	143
Heterogen Atoms	36

Software

Software
Software Name	Purpose
PHENIX	refinement
XDS	data reduction
Aimless	data scaling
MOLREP	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.