4G2B
Structure of the Catalytic Domain of the Salmonella Virulence Factor SseI
Experimental procedure
Experimental method | SINGLE WAVELENGTH |
Source type | SYNCHROTRON |
Source details | NSLS BEAMLINE X29A |
Synchrotron site | NSLS |
Beamline | X29A |
Temperature [K] | 93 |
Detector technology | CCD |
Detector | ADSC QUANTUM 315 |
Wavelength(s) | 1.0809 |
Spacegroup name | P 21 21 21 |
Unit cell lengths | 53.818, 62.506, 110.099 |
Unit cell angles | 90.00, 90.00, 90.00 |
Refinement procedure
Resolution | 27.180 - 2.050 |
R-factor | 0.19579 |
Rwork | 0.194 |
R-free | 0.23780 |
Structure solution method | MOLECULAR REPLACEMENT |
RMSD bond length | 0.022 |
RMSD bond angle | 1.798 |
Data reduction software | HKL-2000 |
Data scaling software | HKL-2000 |
Phasing software | PHASER |
Refinement software | REFMAC (5.5.0044) |
Data quality characteristics
Overall | |
High resolution limit [Å] | 2.050 |
Number of reflections | 22722 |
Crystallization Conditions
crystal 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 |