1WCI

Reactivity modulation of human branched-chain alpha-ketoacid dehydrogenase by an internal molecular switch

X-RAY DIFFRACTION

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Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION	5.5	293	CRYSTALS WERE GROWN AT 20C VIA THE VAPOR DIFFUSION METHOD BY MIXING EQUAL AMOUNTS OF PROTEIN (20-25 MG/ML IN 50 MM HEPES/NAOH, PH 7.5, 250 MM KCL, 0.5 MM PMSF, 1 MM BENZAMIDINE AND 5% (V/V) GLYCEROL) WITH WELL SOLUTION (1.4-1.6 M AMMONIUM SULFATE, 0.1 M NA-CITRATE PH 5.8, 20 MM B-MERCAPTOETHANOL). SERIALLY DILUTED CRUSHED CRYSTALS WERE USED FOR MICRO-SEEDING ONE DAY AFTER THE DROPS WERE SET UP. CRYSTALS APPEARED ONE DAY AFTER SEEDING AND GREW TO A MAXIMUM SIZE OF 120 X 800 UM WITHIN 10 DAYS. CRYSTALS WERE STABILIZED FOR 12 HOURS BY TRANSFER TO FRESH WELL SOLUTION. THEY WERE THEN CRYO-PROTECTED BY STEP-WISE TRANSFER INTO CRYO-BUFFER CONTAINING 1.6 M AMMONIUM SULFATE, 50 MM HEPES, PH 7.5, 100 MM NA-CITRATE, PH 5.8, 100 MM KCL, 50 MM DTT AND UP TO 20% (V/V) GLYCEROL. IT WAS FOUND THAT MN2 IONS COULD REPLACE THE MG2 REQUIRED FOR THE BINDING OF THDP TO THE ENZYME.

Crystal Properties
Matthews coefficient	Solvent content
2.5	53.4

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 145.044	α = 90
b = 145.044	β = 90
c = 69.51	γ = 120

Symmetry
Space Group	P 31 2 1

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	CUSTOM		2003-06-21	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	APS BEAMLINE 19-BM		APS	19-BM

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	1.84	22.83	97.3	0.08	22.5	6		71058		-3	18.23

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	1.84	1.87	80.8		0.8	1.9	5.2

Refinement

Statistics
Diffraction ID	Structure Solution Method	Cross Validation method	Starting model	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	PDB ENTRY 1OLS	1.84	30	69564	1477	97.9	0.149	0.148	0.188	RANDOM	18.29

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]
0.79	0.39		0.79		-1.18

RMS Deviations
Key	Refinement Restraint Deviation
r_dihedral_angle_2_deg	35.754
r_dihedral_angle_4_deg	19.866
r_dihedral_angle_3_deg	13.851
r_dihedral_angle_1_deg	5.899
r_scangle_it	4.707
r_scbond_it	3.027
r_mcangle_it	1.67
r_angle_refined_deg	1.662
r_mcbond_it	0.987
r_nbtor_refined	0.314
r_nbd_refined	0.214
r_symmetry_vdw_refined	0.174
r_symmetry_hbond_refined	0.163
r_xyhbond_nbd_refined	0.154
r_chiral_restr	0.132
r_bond_refined_d	0.02
r_gen_planes_refined	0.009
r_bond_other_d
r_angle_other_deg
r_gen_planes_other
r_nbd_other
r_nbtor_other
r_xyhbond_nbd_other
r_metal_ion_refined
r_metal_ion_other
r_symmetry_vdw_other
r_symmetry_hbond_other
r_symmetry_metal_ion_refined
r_symmetry_metal_ion_other
r_mcbond_other
r_mcangle_other
r_scbond_other
r_scangle_other
r_long_range_B_refined
r_long_range_B_other
r_rigid_bond_restr
r_sphericity_free
r_sphericity_bonded

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	5728
Nucleic Acid Atoms
Solvent Atoms	605
Heterogen Atoms	49

Software

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