2NOP

An unusual twin-His arrangement in the pore of ammonia channels is essential for substrate conductance

X-RAY DIFFRACTION

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Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, SITTING DROP	4.6	298	30% PEG 400, 0.1M SODIUM ACETATE, 0.2M AMMONIUM SULFATE, PH 4.6, VAPOR DIFFUSION, SITTING DROP, TEMPERATURE 298K, pH 4.60

Crystal Properties
Matthews coefficient	Solvent content
3.3	62.77

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 109.879	α = 90
b = 109.879	β = 90
c = 84.17	γ = 120

Symmetry
Space Group	P 63

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	MARMOSAIC 225 mm CCD		2005-06-13	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	SLS BEAMLINE X10SA	0.901031	SLS	X10SA

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	2	50	96	0.068	21.57			36385		-3

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	2	2.1	100		0.428	5.55

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 (All)	R-Factor (Observed)	R-Work	R-Free	R-Free Selection Details	Mean Isotropic B
X-RAY DIFFRACTION	MOLECULAR REPLACEMENT	THROUGHOUT	PDB ENTRY 1XQF	2	15	38983	34486	1856	93.23	0.16082	0.16082	0.15989	0.17815	RANDOM	40.252

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]
1.27	0.63		1.27		-1.9

RMS Deviations
Key	Refinement Restraint Deviation
r_dihedral_angle_2_deg	29.303
r_dihedral_angle_4_deg	21.204
r_dihedral_angle_3_deg	12.496
r_scangle_it	3.735
r_scbond_it	2.656
r_dihedral_angle_1_deg	1.821
r_mcangle_it	1.705
r_angle_refined_deg	1.275
r_mcbond_it	1.081
r_nbtor_refined	0.306
r_nbd_refined	0.195
r_symmetry_vdw_refined	0.172
r_xyhbond_nbd_refined	0.125
r_chiral_restr	0.102
r_symmetry_hbond_refined	0.071
r_bond_refined_d	0.012
r_gen_planes_refined	0.008
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_rigid_bond_restr
r_sphericity_free
r_sphericity_bonded

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	2639
Nucleic Acid Atoms
Solvent Atoms	75
Heterogen Atoms	20

Software

Software
Software Name	Purpose
MOLREP	phasing
REFMAC	refinement
MAR345	data collection
XDS	data reduction
XSCALE	data scaling