6CXK

E. coli DHFR substrate complex with Dihydrofolate

Experimental procedure

Experimental method	SINGLE WAVELENGTH
Source type	SYNCHROTRON
Source details	APS BEAMLINE 31-ID
Synchrotron site	APS
Beamline	31-ID
Temperature [K]	100
Detector technology	CCD
Collection date	2017-11-30
Detector	RAYONIX MX-225
Wavelength(s)	0.97931
Spacegroup name	P 21 21 21
Unit cell lengths	33.698, 51.525, 77.421
Unit cell angles	90.00, 90.00, 90.00

Refinement procedure

Resolution	30.949 - 1.108
R-factor	0.1792
Rwork	0.179
R-free	0.19610
Structure solution method	MOLECULAR REPLACEMENT
Starting model (for MR)	7dfr
RMSD bond length	0.009
RMSD bond angle	1.334
Data reduction software	XDS
Data scaling software	XSCALE
Phasing software	PHASER
Refinement software	PHENIX (1.8.4_1496)

Data quality characteristics

	Overall	Inner shell	Outer shell
Low resolution limit [Å]	30.949	30.949	1.180
High resolution limit [Å]	1.108	3.320	1.108
Rmerge	0.067	0.024	0.861
Rmeas	0.073	0.026	1.051
Number of reflections	53265	2197	7579
<I/σ(I)>	13.44	56.14	1.16
Completeness [%]	97.9	99.1	87.3
Redundancy	6.255	6.693	2.804
CC(1/2)	0.999	0.999	0.571

Crystallization Conditions

crystal ID	method	pH	temperature	details
1	VAPOR DIFFUSION, SITTING DROP	6.5	293.15	Sitting drop of final volume of 0.8 uL was set up by 1:1 v/v mixing of 15 mg/mL E. coli DHFR working stock with reservoir solution containing 0.1M MES pH 6.5, 27.5% PEG 3350, 0.4M MgCl2. E. coli DHFR working stock was prepared from a 1:1 v/v mixture of 30 mg/ml protein in 20 mM Tris pH 8, 1mM DTT with 50 mM HEPES pH 7.3, 100 mM NaCl. Crystals harvested after 2 weeks growth and cryoprotected with mitegen LV oil before flash freezing in N2.