4G2B
Structure of the Catalytic Domain of the Salmonella Virulence Factor SseI
X-RAY DIFFRACTION
Crystallization
Crystalization Experiments | ||||
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ID | Method | pH | Temperature | Details |
1 | VAPOR DIFFUSION, HANGING DROP | 4.6 | 277 | Crystallization screens were conducted using 1:1 sitting drops at RT and 4 C. The C-terminal domain (137-322) (~20mg/mL) gave large rectangular crystals in 1.15M LiSO4, 0.1M NaOAc, pH 4.6 (4 C) when optimized (1:1 hanging drops). However these were very fragile and consisted of multiple lattices overlaid on each other as observed in their diffraction patterns. SseI 137-322 was then reductively methylated and rescreened. It gave multiple crystals of differing morphologies in a number of conditions containing MES, Tris, and HEPES buffers pH 6.0 - 9.0, and 1.6 to 2.0M (NH4)SO4. To obtain single crystals, crystals from 0.1M MES pH 7.1, 1.8M (NH4)SO4 were crushed and microseeded into pre-equilibrated (2 hrs) drops containing protein/reservoir solution (0.1M MES pH 5.5, 1.6M (NH4)SO4). This procedure produced single, small, rectangular crystals. To obtain larger crystals, single crystals obtained in the previous step were macroseeded into pre-equilibrated drops, giving large, thin rectangular plates that were well-diffracting. SeMet-substituted crystals of 137-322 were obtained in the same conditions but gave large crystals directly without any seeding. Crystals were then cryoprotected by transfer in small increments into mother liquor supplemented with 25% glycerol. , VAPOR DIFFUSION, HANGING DROP, temperature 277K |
Crystal Properties | |
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Matthews coefficient | Solvent content |
2.17 | 43.34 |
Crystal Data
Unit Cell | |
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Length ( Å ) | Angle ( ˚ ) |
a = 53.818 | α = 90 |
b = 62.506 | β = 90 |
c = 110.099 | γ = 90 |
Symmetry | |
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Space Group | P 21 21 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 | 93 | CCD | ADSC QUANTUM 315 | M | SINGLE WAVELENGTH |
Radiation Source | |||||
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ID # | Source | Type | Wavelength List | Synchrotron Site | Beamline |
1 | SYNCHROTRON | NSLS BEAMLINE X29A | 1.0809 | NSLS | X29A |
Data Collection
Overall | |||||||||||||||||||
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ID # | Resolution (High) | Resolution (Low) | Percent Possible (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 | 2.05 | 22722 |
Refinement
Statistics | |||||||||||||||||||
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Diffraction ID | Structure Solution Method | Cross Validation method | 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 | 2.05 | 27.18 | 22722 | 1227 | 99.86 | 0.19579 | 0.19353 | 0.2378 | RANDOM | 33.336 |
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] | |
-0.04 | 0.04 |
RMS Deviations | |
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Key | Refinement Restraint Deviation |
r_dihedral_angle_2_deg | 35.117 |
r_dihedral_angle_4_deg | 20.063 |
r_dihedral_angle_3_deg | 16.374 |
r_dihedral_angle_1_deg | 6.357 |
r_scangle_it | 4.975 |
r_scbond_it | 3.222 |
r_mcangle_it | 2.057 |
r_angle_refined_deg | 1.798 |
r_mcbond_it | 1.189 |
r_angle_other_deg | 0.998 |
Non-Hydrogen Atoms Used in Refinement | |
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Non-Hydrogen Atoms | Number |
Protein Atoms | 2719 |
Nucleic Acid Atoms | |
Solvent Atoms | 158 |
Heterogen Atoms |
Software
Software | |
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Software Name | Purpose |
PHASER | phasing |
REFMAC | refinement |
HKL-2000 | data reduction |
HKL-2000 | data scaling |