6W79

Structure of SARS-CoV main protease bound to potent broad-spectrum non-covalent inhibitor X77

X-RAY DIFFRACTION

Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
experimental model	PDB	4MDS

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, HANGING DROP	6	278	3 uL drops that were formed by adding 1 uL of purified SARS-3CLpro (10 mg/mL) that had been incubated for three hours with a 3 molar excess of the of compound X77, and 2 uL of reservoir solution: 3 mM DTT, 50 mM MES pH 6.0, 40 mM KCl, 1% MPD, and 5% PEG-10K

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 108.881	α = 90
b = 81.26	β = 104.231
c = 53.455	γ = 90

Symmetry
Space Group	C 1 2 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	MARMOSAIC 300 mm CCD		2020-03-17	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	SYNCHROTRON	APS BEAMLINE 21-ID-G	0.978	APS	21-ID-G

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (Observed)	Rrim I (All)	Rpim I (All)	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	1.46	100	99.7	0.049	0.022	41.3	4.9		77810			18.31

Highest Resolution Shell
ID #	Resolution (High)	Resolution (Low)	Percent Possible (All)	Percent Possible (Observed)	Rrim I (All)	Rpim I (All)	CC (Half)	Mean I Over Sigma (Observed)	Redundancy	Number Unique Reflections (All)
1	1.46	1.49	99.7		0.62	0.286	0.908	2.6	4.5

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	4MDS	1.46	32.28	1.37	77771	2000	99.5	0.157	0.1564	0.1773	30.07

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	19.2604
f_angle_d	0.8978
f_chiral_restr	0.078
f_plane_restr	0.0056
f_bond_d	0.0054

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	2371
Nucleic Acid Atoms
Solvent Atoms	563
Heterogen Atoms	62

Software

Software
Software Name	Purpose
PHENIX	refinement
HKL-2000	data reduction
SCALEPACK	data scaling
PHENIX	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 R01GM157729.