1OLX

Roles of His291-alpha and His146-beta' in the reductive acylation reaction catalyzed by human branched-chain alpha-ketoacid dehydrogenase

X-RAY DIFFRACTION

---

Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
experimental model	PDB	1OLS	PDB ENTRY 1OLS

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	51

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 145.216	α = 90
b = 145.216	β = 90
c = 69.521	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			2003-03-15	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	2.25	32.18	93.3	0.09	10.2	2.2		37471		-3	11.5

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	2.25	2.25	99.4		0.582	1.6	2.1

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	2.25	32.18	35544	1442	88.4	0.161	0.161	0.214	RANDOM	22.2

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]
2.63	4.2		2.63		-5.26

RMS Deviations
Key	Refinement Restraint Deviation
c_dihedral_angle_d	22.7
c_scangle_it	3.22
c_scbond_it	2.21
c_mcangle_it	2.04
c_angle_deg	1.6
c_mcbond_it	1.31
c_improper_angle_d	1.07
c_bond_d	0.014
c_bond_d_na
c_bond_d_prot
c_angle_d
c_angle_d_na
c_angle_d_prot
c_angle_deg_na
c_angle_deg_prot
c_dihedral_angle_d_na
c_dihedral_angle_d_prot
c_improper_angle_d_na
c_improper_angle_d_prot

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	5751
Nucleic Acid Atoms
Solvent Atoms	371
Heterogen Atoms	41

Software

Software
Software Name	Purpose
CNS	refinement
HKL-2000	data reduction
HKL-2000	data scaling
CNS	phasing