6XB2

Room temperature X-ray crystallography reveals catalytic cysteine in the SARS-CoV-2 3CL Mpro is highly reactive: Insights for enzyme mechanism and drug design

X-RAY DIFFRACTION

Starting Model(s)

Initial Refinement Model(s)
Type	Source	Accession Code	Details
experimental model	PDB	6WQF

Crystallization

Crystalization Experiments
ID	Method	pH	Temperature	Details
1	VAPOR DIFFUSION, SITTING DROP	6.5	293	BIS-TRIS pH=6.5, 20% PEG3350

Crystal Properties
Matthews coefficient	Solvent content
2.07	40.56

Crystal Data

Unit Cell
Length ( Å )	Angle ( ˚ )
a = 45.292	α = 90
b = 54.636	β = 100.739
c = 115.157	γ = 90

Symmetry
Space Group	I 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	293	PIXEL	DECTRIS EIGER R 4M		2020-05-05	M	SINGLE WAVELENGTH

Radiation Source
ID #	Source	Type	Wavelength List	Synchrotron Site	Beamline
1	ROTATING ANODE	RIGAKU MICROMAX-007	1.54

Data Collection

Overall
ID #	Resolution (High)	Resolution (Low)	Percent Possible (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	2.1	28.29	99.9	0.036	0.998	11.3	3.9		16266			42.35

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	2.1	2.16	99.9		0.658	0.46	1.2

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	6WQF	2.1	18.86	1.35	16240	780	99.86	0.1984	0.1956	0.2572	46.92

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	19.2779
f_angle_d	0.9175
f_chiral_restr	0.0527
f_bond_d	0.0076
f_plane_restr	0.0058

Non-Hydrogen Atoms Used in Refinement
Non-Hydrogen Atoms	Number
Protein Atoms	2367
Nucleic Acid Atoms
Solvent Atoms	47
Heterogen Atoms	22

Software

Software
Software Name	Purpose
PHENIX	refinement
CrysalisPro	data reduction
Aimless	data scaling
MOLREP	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.