1SKU

E. coli Aspartate Transcarbamylase 240's Loop Mutant (K244N)

X-RAY DIFFRACTION

---

Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
experimental model	PDB	1EZZ	A consensus model using overlayed previously published pdb entry 1EZZ (mutant P268A catalytic chain) and 1NBE (T82A regulatory chain) and wild type 3AT1 was used.
experimental model	PDB	1NBE	A consensus model using overlayed previously published pdb entry 1EZZ (mutant P268A catalytic chain) and 1NBE (T82A regulatory chain) and wild type 3AT1 was used.
experimental model	PDB	3AT1	A consensus model using overlayed previously published pdb entry 1EZZ (mutant P268A catalytic chain) and 1NBE (T82A regulatory chain) and wild type 3AT1 was used.

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, HANGING DROP	7	298	Prior to crystallization the enzyme was dialyzed into 40 mM KH2PO4, 2.0 mM 2-mercaptoethanol, 0.2 mM EDTA, pH 7.0 for 24 hours. Single crystals of the K244N mutant were obtained by mixing a 20 mg/ml filtered solution (0.22 m) of the K244N enzyme with a solution of 17% (w/v) PEG 1450, 50 mM malonate, 0.2 mM EDTA, 1 mM sodium azide and 20 mM Bis-Tris buffer pH 7.0 in a 1:1 ratio (v/v), VAPOR DIFFUSION, HANGING DROP, temperature 298K

Crystal Properties
Matthews coefficient	Solvent content
3.04	59.22

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 125.67	α = 90
b = 125.67	β = 90
c = 198.2	γ = 120

Symmetry
Space Group	H 3

Diffraction

Diffraction Experiment
ID #	Crystal ID	Scattering Type	Data Collection Temperature	Detector	Detector Type	Details	Collection Date	Monochromator	Protocol
1	1	x-ray	100	CCD	BRANDEIS - B4		2003-12-30	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	NSLS BEAMLINE X12C	1.00704	NSLS	X12C

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	2.59	30		0.039	13.3	6.5	36343	34988

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	2.59	2.68	89.8		0.327	12.2	2.62

Refinement

Statistics
Diffraction ID	Structure Solution Method	Cross Validation method	Starting model	Resolution (High)	Resolution (Low)	Number Reflections (All)	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	A consensus model using overlayed previously published pdb entry 1EZZ (mutant P268A catalytic chain) and 1NBE (T82A regulatory chain) and wild type 3AT1 was used.	2.6	29.55	36343	30529	1589	89.44	0.20186	0.20122	0.23117	RANDOM	34.638

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]
0.58	0.29		0.58		-0.86

RMS Deviations
Key	Refinement Restraint Deviation
r_dihedral_angle_1_deg	10.412
r_scangle_it	8.632
r_scbond_it	6.115
r_angle_refined_deg	4.586
r_mcangle_it	3.837
r_mcbond_it	2.358
r_symmetry_hbond_refined	0.472
r_symmetry_vdw_refined	0.465
r_nbd_refined	0.393
r_xyhbond_nbd_refined	0.325
r_chiral_restr	0.318
r_bond_refined_d	0.063
r_gen_planes_refined	0.02
r_bond_other_d
r_angle_other_deg
r_dihedral_angle_2_deg
r_dihedral_angle_3_deg
r_dihedral_angle_4_deg
r_gen_planes_other
r_nbd_other
r_nbtor_refined
r_nbtor_other
r_xyhbond_nbd_other
r_metal_ion_refined
r_metal_ion_other
r_symmetry_vdw_other
r_symmetry_hbond_other
r_mcbond_other
r_rigid_bond_restr
r_sphericity_free
r_sphericity_bonded

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	7147
Nucleic Acid Atoms
Solvent Atoms	66
Heterogen Atoms	16

Software

Software
Software Name	Purpose
REFMAC	refinement
DENZO	data reduction
SCALEPACK	data scaling
AMoRE	phasing