7TFP

Human Ornithine Aminotransferase cocrystallized with its inhibitor, (1S,3S)-3-amino-4-(difluoromethylene)cyclopentane-1-carboxylic acid.

X-RAY DIFFRACTION

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, HANGING DROP	7.8	293	After purification, hOAT was buffer exchanged into the crystallization buffer (50 mM Tricine pH 7.8) supplemented with 1 mM 2-ketoglutarate. The protein was concentrated to 6.5 mg/mL. Previously reported crystallization conditions were optimized using the hanging drop vapor diffusion method by varying PEG 6000 (8-12%), NaCl (100-250 mM), and glycerol (0%-10%) with 100 mM Tricine pH 7.8 being kept constant as the buffer. For each hanging drop, 2 uL of protein solution was mixed with an equal volume of well solution and 0.5 uL of ligand. The crystals with the best morphology and size grew in a final condition containing 12% PEG 6000, 200 mM NaCl, 10% glycerol, and 100 mM Tricine pH 7.8. Crystals were transferred to a cryo-protectant solution (well solution supplemented with 30% glycerol) and flash-frozen in liquid nitrogen.

Crystal Properties
Matthews coefficient	Solvent content
2.66	53.72

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 115.17	α = 90
b = 115.17	β = 90
c = 186.81	γ = 120

Symmetry
Space Group	P 32 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	PIXEL	DECTRIS EIGER X 9M		2021-07-03	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	APS BEAMLINE 21-ID-D	1.127	APS	21-ID-D

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	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	2.71	57.58	96.5	0.986	6	6.4		37903			53.9

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	CC (Half)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
1	2.71	2.78			0.31

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	FREE R-VALUE	1OAT	2.71	43.99	1.34	37851	1976	95.6	0.229	0.227	0.268	54.95

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	13.289
f_angle_d	0.485
f_chiral_restr	0.043
f_plane_restr	0.004
f_bond_d	0.002

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	9468
Nucleic Acid Atoms
Solvent Atoms	252
Heterogen Atoms	30

Software

Software
Software Name	Purpose
PHENIX	refinement
xia2	data reduction
xia2	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.