2C2T
Human Dihydrofolate Reductase Complexed With NADPH and 2,4-Diamino-5-((7,8-dicarbaundecaboran-7-yl)methyl)-6-methylpyrimidine, a novel boron containing, nonclassical Antifolate
X-RAY DIFFRACTION
Crystallization
Crystalization Experiments | ||||
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ID | Method | pH | Temperature | Details |
1 | VAPOR DIFFUSION, HANGING DROP | 8 | 277 | THE TERNARY COMPLEX OF DHFR WITH NADPH AND 39B 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), 5% GLYCEROL, 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. NOTE THAT THE INHIBITOR IS ACTUALLY A RACEMIC MIXTURE OF 39B AND ITS ENANTIOMER, HERE CALLED 39E. IT IS THE RACEMATE THAT IS BOUND IN THE CRYSTAL, REPRESENTED IN THE COORDINATES AS A 1:1 STATISTICALLY-DISORDERED MIXTURE OF 39B AND 39E. |
Crystal Properties | |
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Matthews coefficient | Solvent content |
2.3 | 46.7 |
Crystal Data
Unit Cell | |
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Length ( Å ) | Angle ( ˚ ) |
a = 87.628 | α = 90 |
b = 94.354 | β = 90 |
c = 96.032 | γ = 90 |
Symmetry | |
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Space Group | C 2 2 21 |
Diffraction
Diffraction Experiment | ||||||||||||||
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ID # | Crystal ID | Scattering Type | Data Collection Temperature | Detector | Detector Type | Details | Collection Date | Monochromator | Protocol | |||||
1 | 1 | x-ray | 100 | IMAGE PLATE | MARRESEARCH | MIRROR | 1999-03-03 | M | SINGLE WAVELENGTH |
Radiation Source | |||||
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ID # | Source | Type | Wavelength List | Synchrotron Site | Beamline |
1 | SYNCHROTRON | SSRL BEAMLINE BL9-1 | SSRL | BL9-1 |
Data Collection
Overall | |||||||||||||||||||
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ID # | Resolution (High) | Resolution (Low) | Percent Possible (Observed) | R Merge 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 | 1.5 | 35 | 98.4 | 0.06 | 8.4 | 2.9 | 62594 | 19 |
Highest Resolution Shell | |||||||||||||||||||
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ID # | Resolution (High) | Resolution (Low) | Percent Possible (All) | Percent Possible (Observed) | R Merge I (Observed) | Mean I Over Sigma (Observed) | Redundancy | Number Unique Reflections (All) | |||||||||||
1 | 1.5 | 1.54 | 90.1 | 0.45 | 1.7 | 2.1 |
Refinement
Statistics | |||||||||||||||||||
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Diffraction ID | Structure Solution Method | Cross Validation method | Starting model | Resolution (High) | Resolution (Low) | Number Reflections (Observed) | Number Reflections (R-Free) | Percent Reflections (Observed) | R-Factor (Observed) | R-Work | R-Free | R-Free Selection Details | Mean Isotropic B | ||||||
X-RAY DIFFRACTION | MOLECULAR REPLACEMENT | THROUGHOUT | UNPUBLISHED HUMAN DHFR STRUCTURE | 1.5 | 20 | 59389 | 3168 | 98.1 | 0.16 | 0.158 | 0.213 | RANDOM | 17.53 |
Temperature Factor Modeling | ||||||
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Anisotropic B[1][1] | Anisotropic B[1][2] | Anisotropic B[1][3] | Anisotropic B[2][2] | Anisotropic B[2][3] | Anisotropic B[3][3] | |
-0.19 | 0.52 | -0.33 |
RMS Deviations | |
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Key | Refinement Restraint Deviation |
r_dihedral_angle_2_deg | 39.148 |
r_dihedral_angle_3_deg | 12.361 |
r_dihedral_angle_4_deg | 12.057 |
r_dihedral_angle_1_deg | 5.892 |
r_scangle_it | 3.438 |
r_scbond_it | 2.642 |
r_mcangle_it | 1.684 |
r_angle_refined_deg | 1.451 |
r_mcbond_it | 1.413 |
r_angle_other_deg | 1.202 |
Non-Hydrogen Atoms Used in Refinement | |
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Non-Hydrogen Atoms | Number |
Protein Atoms | 3004 |
Nucleic Acid Atoms | |
Solvent Atoms | 607 |
Heterogen Atoms | 186 |
Software
Software | |
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Software Name | Purpose |
REFMAC | refinement |
MOSFLM | data reduction |
SCALA | data scaling |
AMoRE | phasing |