6P27

Structure of a nested set of N-terminally extended MHC I-peptides provides novel insights into antigen processing and presentation

X-RAY DIFFRACTION

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, HANGING DROP		298	0.2 M ammonium sulfate, 18% PEG4000, 0.1 M sodium cacodylate, pH 5.7

Crystal Properties
Matthews coefficient	Solvent content
2.55	51.79

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 50.607	α = 90
b = 81.318	β = 90
c = 110.728	γ = 90

Symmetry
Space Group	P 21 21 21

Diffraction

Diffraction Experiment
ID #	Crystal ID	Scattering Type	Data Collection Temperature	Detector	Detector Type	Details	Collection Date	Monochromator	Protocol
1	1	x-ray	80	CCD	MARMOSAIC 300 mm CCD		2018-08-16	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	APS BEAMLINE 21-ID-F	0.987	APS	21-ID-F

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	1.59	20	99.3	0.052	22.1	8.1		61436

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
1	1.59	1.65	96			6.5

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	PDB entry 1AGB	1.593	19.995	1.37	61436	5815	99.15	0.1929	0.1918	0.2127

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	13.707
f_angle_d	1.076
f_chiral_restr	0.08
f_bond_d	0.006
f_plane_restr	0.005

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	3147
Nucleic Acid Atoms
Solvent Atoms	236
Heterogen Atoms

Software

Software
Software Name	Purpose
PHENIX	refinement
XDS	data reduction
XDS	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.