4G29

Structure of the Catalytic Domain of the Salmonella Virulence Factor SseI

X-RAY DIFFRACTION

---

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, HANGING DROP	4.6	277.15	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 277.15K

Crystal Properties
Matthews coefficient	Solvent content
2.08	40.95

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 52.256	α = 90
b = 52.256	β = 90
c = 132.146	γ = 90

Symmetry
Space Group	P 41 21 2

Diffraction

Diffraction Experiment
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
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	NSLS BEAMLINE X29A	0.97900	NSLS	X29A

Data Collection

Overall
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	1.7						19151

Refinement

Statistics
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	SAD	THROUGHOUT	1.7	19.08	19151	1045	100	0.18469	0.18318	0.21364	RANDOM	11.984

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]
-0.07			-0.07		0.13

RMS Deviations
Key	Refinement Restraint Deviation
r_dihedral_angle_2_deg	37.044
r_dihedral_angle_4_deg	20.858
r_dihedral_angle_3_deg	12.557
r_dihedral_angle_1_deg	6.183
r_scangle_it	4.222
r_scbond_it	2.982
r_mcangle_it	1.705
r_angle_refined_deg	1.647
r_mcbond_it	1.011
r_angle_other_deg	0.998
r_mcbond_other	0.339
r_chiral_restr	0.105
r_bond_refined_d	0.019
r_gen_planes_refined	0.008
r_bond_other_d	0.006
r_gen_planes_other	0.001
r_nbd_refined
r_nbd_other
r_nbtor_refined
r_nbtor_other
r_xyhbond_nbd_refined
r_xyhbond_nbd_other
r_metal_ion_refined
r_metal_ion_other
r_symmetry_vdw_refined
r_symmetry_vdw_other
r_symmetry_hbond_refined
r_symmetry_hbond_other
r_symmetry_metal_ion_refined
r_symmetry_metal_ion_other
r_rigid_bond_restr
r_sphericity_free
r_sphericity_bonded

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	1335
Nucleic Acid Atoms
Solvent Atoms	137
Heterogen Atoms

Software

Software
Software Name	Purpose
HKL-2000	data collection
REFMAC	refinement
HKL-2000	data reduction
HKL-2000	data scaling