2INQ

Neutron Crystal Structure of Escherichia coli Dihydrofolate Reductase Bound to the Anti-cancer drug, Methotrexate

Experimental procedure

Experimental method	LAUE
Temperature [K]	293
Detector technology	AREA DETECTOR
Collection date	2005-02-15
Detector	TIME-OF-FLIGHT MULTIWIRE HE3 NEUTRON DETECTOR
Wavelength(s)	0.6-7.0
Spacegroup name	P 61
Unit cell lengths	93.120, 93.120, 73.870
Unit cell angles	90.00, 90.00, 120.00

Refinement procedure

Resolution	6.500 - 2.200
R-free	0.23300
Structure solution method	FOURIER SYNTHESIS
Starting model (for MR)	3DRC (293 K E. COLI DHFR/MTX X-RAY STRUCTURE 1.7A RESOLUTION)
RMSD bond length	0.046
RMSD bond angle	0.048
Data reduction software	d*TREK (MODIFIED FOR TIME-OF- FLIGHT SPOT INTEGRATION)
Data scaling software	d*TREK (modified for Time-of-Flight data collection)
Phasing software	SHELXL-97
Refinement software	SHELXL-97

Data quality characteristics

	Overall	Outer shell
Low resolution limit [Å]	38.600	2.290
High resolution limit [Å]	2.170	2.170
Rmerge	0.136
Number of reflections	14213
<I/σ(I)>	3.7	1.7
Completeness [%]	79.7	63.7
Redundancy	2.9	1.7

Crystallization Conditions

crystal ID	method	pH	temperature	details
1		7.5	277	16% (v/v) Polyethylene Glycol 400, 0.2 M CaCl2, 0.1 M Na-HEPES (pH = 7.5); complex [] = 50 mg/ml, Microbatch under parrafin oil, temperature 277K, pH 7.50