2NMR

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

X-RAY DIFFRACTION

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, SITTING DROP	4.6	298	25% PEG 550, 0.1M sodium acetate, 0.2M ammonium sulfate, pH 4.6, VAPOR DIFFUSION, SITTING DROP, temperature 298K

Crystal Properties
Matthews coefficient	Solvent content
3.3	62.77

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 109.799	α = 90
b = 109.799	β = 90
c = 84.407	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		2006-05-24	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	SLS BEAMLINE X06SA	0.98007	SLS	X06SA

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	2.1	50	99.5	0.072	13.53			33648		-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	2.1	2.2	99.7		0.699	3.14

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	2.1	15	33825	31893	1702	99.63	0.16592	0.16592	0.16438	0.19549	RANDOM	48.676

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]
1.03	0.51		1.03		-1.54

RMS Deviations
Key	Refinement Restraint Deviation
r_dihedral_angle_2_deg	28.812
r_dihedral_angle_4_deg	20.658
r_dihedral_angle_3_deg	14.062
r_scangle_it	4.329
r_scbond_it	3.12
r_mcangle_it	1.979
r_dihedral_angle_1_deg	1.849
r_angle_refined_deg	1.397
r_mcbond_it	1.269
r_nbtor_refined	0.31

RMS Deviations
Key	Refinement Restraint Deviation
r_dihedral_angle_2_deg	28.812
r_dihedral_angle_4_deg	20.658
r_dihedral_angle_3_deg	14.062
r_scangle_it	4.329
r_scbond_it	3.12
r_mcangle_it	1.979
r_dihedral_angle_1_deg	1.849
r_angle_refined_deg	1.397
r_mcbond_it	1.269
r_nbtor_refined	0.31
r_nbd_refined	0.205
r_symmetry_vdw_refined	0.177
r_symmetry_hbond_refined	0.172
r_xyhbond_nbd_refined	0.125
r_chiral_restr	0.11
r_bond_refined_d	0.012
r_gen_planes_refined	0.009

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	2639
Nucleic Acid Atoms
Solvent Atoms	94
Heterogen Atoms	15

Software

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

RCSB PDB Core Operations are funded by the National Science Foundation (DBI-1832184), the US Department of Energy (DE-SC0019749), and the National Cancer Institute, National Institute of Allergy and Infectious Diseases, and National Institute of General Medical Sciences of the National Institutes of Health under grant R01GM133198.