7SU1

Crystal structure of an acidic pH-selective Ipilimumab variant Ipi.106 in complex with CTLA-4

X-RAY DIFFRACTION

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, SITTING DROP		293	0.2 M sodium citrate tribasic dehydrate, 22% PEG 3,350

Crystal Properties
Matthews coefficient	Solvent content
3.62	65.98

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 109.66	α = 90
b = 109.66	β = 90
c = 297.6	γ = 90

Symmetry
Space Group	I 41 2 2

Diffraction

Diffraction Experiment
ID #	Crystal ID	Scattering Type	Data Collection Temperature	Detector	Detector Type	Details	Collection Date	Monochromator	Protocol
1	1	x-ray	100	PIXEL	DECTRIS EIGER2 X 9M		2020-10-28	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	APS BEAMLINE 17-ID	1.0	APS	17-ID

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	R Merge I (Observed)	Rpim I (All)	CC (Half)	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	2.526	50	94.6	0.101	0.029	0.999	15.9	13.3		28083			65.73

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	Rpim I (All)	CC (Half)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
1	2.526	2.652			0.547	0.64	1.5

Refinement

Statistics
Diffraction ID	Structure Solution Method	Cross Validation method	Starting model	Resolution (High)	Resolution (Low)	Cut-off Sigma (F)	Number Reflections (Observed)	Number Reflections (R-Free)	Percent Reflections (Observed)	R-Factor (Observed)	R-Work	R-Free	Mean Isotropic B
X-RAY DIFFRACTION	MOLECULAR REPLACEMENT	FREE R-VALUE	5TRU, 4NM4, 3OSK	2.53	37.52	1.35	28062	1440	90.6	0.2083	0.2059	0.2514	75.45

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
f_dihedral_angle_d	6.6366
f_angle_d	1.1118
f_chiral_restr	0.0585
f_bond_d	0.009
f_plane_restr	0.0074

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	4115
Nucleic Acid Atoms
Solvent Atoms	26
Heterogen Atoms	14

Software

Software
Software Name	Purpose
PHENIX	refinement
XDS	data reduction
XSCALE	data scaling
PHASER	phasing

RCSB PDB Core Operations are funded by the U.S. National Science Foundation (DBI-2321666), 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.