Selenium-Assisted Nucleic Acid Crystallography: Use of Phosphoroselenoates for MAD Phasing of a DNA Structure
X-RAY DIFFRACTION
Crystallization
| Crystalization Experiments | ||||
|---|---|---|---|---|
| ID | Method | pH | Temperature | Details |
| 1 | VAPOR DIFFUSION, SITTING DROP | 7 | 291 | 0.5mM DNA, 4mM-15mM magnesium chloride, 50mM sodium cacodylate, 2mM-8mM spermine tetrahydrochloride and reservoir 30% 2-methyl-2,4-pentanediol, pH 7.0, VAPOR DIFFUSION, SITTING DROP, temperature 291.0K |
| Crystal Properties | |
|---|---|
| Matthews coefficient | Solvent content |
| 1.32 | 5.98 |
Crystal Data
| Unit Cell | |
|---|---|
| Length ( Å ) | Angle ( ˚ ) |
| a = 17.778 | α = 90 |
| b = 31.348 | β = 90 |
| c = 44.116 | 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 | 120 | CCD | MARRESEARCH | 2002-01-22 | M | MAD | ||||||
| Radiation Source | |||||
|---|---|---|---|---|---|
| ID # | Source | Type | Wavelength List | Synchrotron Site | Beamline |
| 1 | SYNCHROTRON | APS BEAMLINE 5ID-B | 0.9561, 0.9787, 0.9784 | APS | 5ID-B |
Data Collection
| Overall | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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 | 1.1 | 20 | 97.7 | 0.041 | 22.7 | 7.47 | 10197 | 9718 | |||||||||||
| Highest Resolution Shell | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 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 | 1.14 | 95.4 | 0.075 | 15.85 | 7.47 | 1802 | |||||||||||||
Refinement
| Statistics | |||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Diffraction ID | Structure Solution Method | Resolution (High) | Resolution (Low) | Number Reflections (All) | Number Reflections (Observed) | Number Reflections (R-Free) | Percent Reflections (Observed) | R-Work (Depositor) | R-Work (DCC) | R-Free (Depositor) | R-Free (DCC) | R-Free Selection Details | Mean Isotropic B | ||||||
| X-RAY DIFFRACTION | MAD | 1.1 | 20 | 9718 | 9718 | 508 | 97.7 | 0.097 | 0.11 | 0.129 | 0.14 | random | 6.9 | ||||||
| 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] | |
| RMS Deviations | |
|---|---|
| Key | Refinement Restraint Deviation |
| s_bond_d | 0.028 |
| s_angle_d | 0.022 |
| Non-Hydrogen Atoms Used in Refinement | |
|---|---|
| Non-Hydrogen Atoms | Number |
| Protein Atoms | |
| Nucleic Acid Atoms | 245 |
| Solvent Atoms | 73 |
| Heterogen Atoms | 15 |
Software
| Software | |
|---|---|
| Software Name | Purpose |
| SHELXL-97 | refinement |
| SCALEPACK | data scaling |
| CNS | refinement |
| DENZO | data reduction |
| CNS | phasing |














