3B6H

Crystal structure of human prostacyclin synthase in complex with inhibitor minoxidil

X-RAY DIFFRACTION

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Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, HANGING DROP	8	277	Crystallization of native human prostacyclin synthase (hPGIS). The native recombinant PGIS (25 mg/ml in the gel filtration buffer containing 20 mM Tris, pH 8.0 and 150 mM NaCl) was found to crystallize spontaneously into needle clusters in the Eppendorf tube when stored at 4 C for about a week. A combination of microseeding technique and the hanging-drop vapor-diffusion method was then used to improve crystal quality. Specifically, seed stock was prepared by crushing these initial PGIS needle clusters with the Seed Bead Kit (Hampton Research). Following four 10-fold serial dilutions of the seed stock using the gel filtration buffer, 1 microliter of diluted seeds was added into a 10 microliter drop of freshly concentrated PGIS sample, and equilibrated at 4 C against 450 microliter of the gel filtration buffer. Crystallization of hPGIS-minoxidil complex: The inhibitor-enzyme complex was prepared by adding minoxidil (final concentration 0.1 mM) to a 20 mg/ml hPGIS stock solution. Crystals of the complex were then obtained by co-crystallization, with the technique described above using ligand-free hPGIS microcrystals as seeds., VAPOR DIFFUSION, HANGING DROP, temperature 277K

Crystal Properties
Matthews coefficient	Solvent content
2.35	47.7

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 68.762	α = 90
b = 106.072	β = 91.81
c = 73.901	γ = 90

Symmetry
Space Group	P 1 21 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	ADSC QUANTUM 210		2006-09-22	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	NSRRC BEAMLINE BL13C1	0.97622	NSRRC	BL13C1

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	R Sym 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	1.62	30	99.5	0.04	16.1	3.7	134319	133648	1	1

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	R-Sym I (Observed)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
	1.62	1.66	97.5		0.323	2

Refinement

Statistics
Diffraction ID	Structure Solution Method	Cross Validation method	Starting model	Resolution (High)	Resolution (Low)	Cut-off Sigma (I)	Cut-off Sigma (F)	Number Reflections (All)	Number Reflections (Observed)	Number Reflections (R-Free)	Percent Reflections (Observed)	R-Factor (All)	R-Factor (Observed)	R-Work	R-Free	R-Free Selection Details	Mean Isotropic B
X-RAY DIFFRACTION	MOLECULAR REPLACEMENT	THROUGHOUT	PDB ENTRY 2IAG	1.62	29.09	1	1	133648	126835	6770	99.56	0.209	0.20412	0.20284	0.22805	RANDOM	21.337

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]

RMS Deviations
Key	Refinement Restraint Deviation
r_dihedral_angle_2_deg	30.743
r_dihedral_angle_4_deg	14.624
r_dihedral_angle_3_deg	14.306
r_dihedral_angle_1_deg	5.12
r_scangle_it	2.201
r_scbond_it	1.434
r_angle_refined_deg	1.046
r_mcangle_it	1.012
r_mcbond_it	0.599
r_nbtor_refined	0.304
r_nbd_refined	0.193
r_symmetry_vdw_refined	0.152
r_symmetry_hbond_refined	0.108
r_xyhbond_nbd_refined	0.102
r_chiral_restr	0.07
r_bond_refined_d	0.007
r_gen_planes_refined	0.003

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	7631
Nucleic Acid Atoms
Solvent Atoms	765
Heterogen Atoms	156

Software

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