1KMS

HUMAN DIHYDROFOLATE REDUCTASE COMPLEXED WITH NADPH AND 6-([5-QUINOLYLAMINO]METHYL)-2,4-DIAMINO-5-METHYLPYRIDO[2,3-D]PYRIMIDINE (SRI-9439), A LIPOPHILIC ANTIFOLATE

X-RAY DIFFRACTION

Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
other		UNPUBLISHED HUMAN DHFR STRUCTURE.

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, HANGING DROP	8	277	THE TERNARY COMPLEX OF DHFR WITH NADPH AND SRI-9439 WAS FORMED BY MIXING HUMAN DHFR (20 MG/ML IN 25 MM KPO4 (PH 7.0), 0.1 MM EDTA, AND 3 MM NAN3) WITH 60 MM NADPH, FOLLOWED 15 MINUTES LATER BY 60 MM OF INHIBITOR IN DMSO (FINAL CONCENTRATIONS OF 2 MM NADPH AND 2 MM INHIBITOR). THIS COMPLEX SOLUTION WAS MIXED WITH AN EQUAL VOLUME OF PRECIPITANT CONTAINING 24-33% PEG 4000, 0.2 M LI2SO4, 0.1 M TRIS CL (PH 7.9-8.4), AND EQUILIBRATED WITH THE PRECIPITANT BY HANGING DROP VAPOR DIFFUSION AT 277 K. THE CRYSTAL GREW IN ABOUT 3 WEEKS. THE CRYSTAL WAS FLASH-COOLED DIRECTLY IN LIQUID NITROGEN AFTER HARVESTING INTO MOTHER LIQUOR CONTAINING 10% GLYCEROL., pH 8.00, VAPOR DIFFUSION, HANGING DROP

Crystal Properties
Matthews coefficient	Solvent content
2.23	46

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 41.467	α = 90
b = 55.275	β = 90
c = 82.799	γ = 90

Symmetry
Space Group	P 21 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	IMAGE PLATE	MARRESEARCH	PT-COATED MIRROR	1997-06-25	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	SSRL BEAMLINE BL7-1		SSRL	BL7-1

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	R Merge I (Observed)	R Sym I (Observed)	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	1.09	20	99.6	0.047	0.047	9.4	3.6	79611	79611			10.8

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	R Merge I (Observed)	R-Sym I (Observed)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
	1.09	1.15	99.1		0.422	0.422	2.3	3.3

Refinement

Statistics
Diffraction ID	Structure Solution Method	Cross Validation method	Starting model	Resolution (High)	Resolution (Low)	Number Reflections (All)	Number Reflections (Observed)	Number Reflections (R-Free)	Percent Reflections (Observed)	R-Work	R-Free	R-Free Selection Details	Mean Isotropic B
X-RAY DIFFRACTION	MOLECULAR REPLACEMENT	THROUGHOUT	UNPUBLISHED HUMAN DHFR STRUCTURE.	1.09	20	79411	79411	3988	99.6	0.1306	0.1726	5% OF THE REFLECTIONS WERE RANDOMLY SELECTED FOR THE TEST SET.

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]

Coordinate Error
Structure Solution Method	Refinement High Resolution	Refinement Low Resolution
66	1406.12	1927.22

RMS Deviations
Key	Refinement Restraint Deviation
s_approx_iso_adps	0.098
s_non_zero_chiral_vol	0.086
s_zero_chiral_vol	0.076
s_similar_adp_cmpnt	0.05
s_angle_d	0.032
s_from_restr_planes	0.0293
s_anti_bump_dis_restr	0.023
s_bond_d	0.013
s_rigid_bond_adp_cmpnt	0.005
s_similar_dist

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	1606
Nucleic Acid Atoms
Solvent Atoms	399
Heterogen Atoms	83

Software

Software
Software Name	Purpose
AMoRE	phasing
SHELXL-97	refinement
MOSFLM	data reduction
CCP4	data scaling

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 R01GM157729.