7TA1

Human Ornithine Aminotransferase (hOAT) soaked with gamma-Aminobutyric acid

Experimental procedure

Experimental method	SINGLE WAVELENGTH
Source type	SYNCHROTRON
Source details	APS BEAMLINE 21-ID-D
Synchrotron site	APS
Beamline	21-ID-D
Temperature [K]	100
Detector technology	PIXEL
Collection date	2021-07-03
Detector	DECTRIS EIGER X 9M
Wavelength(s)	1.1271
Spacegroup name	P 31 2 1
Unit cell lengths	114.607, 114.607, 349.326
Unit cell angles	90.00, 90.00, 120.00

Refinement procedure

Resolution	99.250 - 2.200
R-factor	0.2552
Rwork	0.251
R-free	0.26810
Structure solution method	MOLECULAR REPLACEMENT
Starting model (for MR)	1oat
RMSD bond length	0.004
RMSD bond angle	0.818
Data reduction software	autoPROC
Data scaling software	Aimless
Phasing software	PHASER
Refinement software	PHENIX (1.19.2_4158)

Data quality characteristics

	Overall	Outer shell
Low resolution limit [Å]	99.250	2.120
High resolution limit [Å]	2.010	2.010
Number of reflections	177531	25577
<I/σ(I)>	6.7
Completeness [%]	99.8	99.9
Redundancy	6.1
CC(1/2)	0.993	0.417

Crystallization Conditions

crystal ID	method	pH	temperature	details
1	VAPOR DIFFUSION, HANGING DROP	7.8	293	Once hOAT was purified, it was transferred to a 10 kDa centrifugal filter tube and concentrated to ~6 mg/mL. The holoenzyme crystals were first grown via a hanging drop vapor diffusion method. Each drop contained 2 uL of protein and 2 uL of well solution. The best crystallization condition contained 8% PEG 6000, 100 mM NaCl, 5% glycerol, and 50 mM Tricine pH 7.8. Once holoenzyme crystals reached their maximum size within seven days, 1 uL of 10 mM GABA was added to the drop with crystals. The crystals were soaked for different time periods from 50 minutes to 2.5 hours. After soaking, crystals were transferred into a cryoprotective solution (well solution supplemented with 30% glycerol), and then flash-frozen in liquid nitrogen.