9N6F | pdb_00009n6f

X-ray structure of SARS-CoV-2 main protease M165I covalently bound to inhibitor GRL-051-22 at 1.90 A

• PDB DOI: https://doi.org/10.2210/pdb9N6F/pdb

• Classification: VIRAL PROTEIN
• Organism(s): Severe acute respiratory syndrome coronavirus 2
• Expression System: Escherichia coli
• Mutation(s): Yes 


• Deposited: 2025-02-05 Released: 2025-11-26 
• Deposition Author(s): Beechboard, S.N., Meadows, M.S., Ghosh, A.K., Center for Structural Biology of Infectious Diseases (CSBID), Mesecar, A.D.
• Funding Organization(s): National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID), National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 1.90 Å
• R-Value Free: 
  0.216 (Depositor), 0.215 (DCC) 
• R-Value Work: 
  0.162 (Depositor), 0.163 (DCC) 
• R-Value Observed: 
  0.165 (Depositor) 

Starting Model: experimental

Literature

X-ray structure of SARS-CoV-2 main protease M165I covalently bound to inhibitor GRL-051-22 at 1.90 A

Beechboard, S.N., Mesecar, A.D., Center for Structural Biology of Infectious Diseases (CSBID), Ghosh, A.K.

To be published.

Biological Assembly 1  

Global Symmetry: Cyclic - C2  (Explore in 3D)
Global Stoichiometry: Homo 2-mer - A2 

Biological assembly 1 assigned by authors and generated by PISA (software)

Biological Assembly Evidence: gel filtration

Macromolecule Content 

• Total Structure Weight: 34.38 kDa 
• Atom Count: 2,841 
• Modeled Residue Count: 306 
• Deposited Residue Count: 306 
• Unique protein chains: 1

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details	Image
3C-like proteinase nsp5	A	306	Severe acute respiratory syndrome coronavirus 2	Mutation(s): 1  Gene Names: rep, 1a-1b EC: 3.4.22.69
UniProt
Find proteins for P0DTD1 (Severe acute respiratory syndrome coronavirus 2) Explore P0DTD1  Go to UniProtKB:  P0DTD1

Small Molecules

Ligands 2 Unique
ID	Chains	Name / Formula / InChI Key	2D Diagram
A1BFE (Subject of Investigation/LOI)	B [auth A]	(3S)-N-{(1Z,2S)-1-imino-3-[(3S)-2-oxopyrrolidin-3-yl]propan-2-yl}-2-[3-methyl-N-(trifluoroacetyl)-L-valyl]-1,2,3,4-tetrahydroisoquinoline-3-carboxamide C25 H32 F3 N5 O4 PFRRKDXMXGNRNI-DSLXNQLJSA-N
NA	C [auth A], D [auth A]	SODIUM ION Na FKNQFGJONOIPTF-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 1.90 Å
• R-Value Free:  0.216 (Depositor), 0.215 (DCC) 
• R-Value Work:  0.162 (Depositor), 0.163 (DCC) 
• R-Value Observed: 0.165 (Depositor) 

Space Group: C 1 2 1

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 97.112	α = 90
b = 81.915	β = 117.307
c = 54.337	γ = 90

Software Package:

Software Name	Purpose
PHENIX	refinement
CrysalisPro	data reduction
CrysalisPro	data scaling
PHENIX	phasing

Structure Validation

Entry History 

& Funding Information

Deposition Data

• Released Date: 2025-11-26 
Deposition Author(s): Beechboard, S.N., Meadows, M.S., Ghosh, A.K., Center for Structural Biology of Infectious Diseases (CSBID), Mesecar, A.D.

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Funding Organization	Location	Grant Number
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)	United States	HHSN272201700060C
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)	United States	1RO1 AI158649
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)	United States	GM132024
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)	United States	S10 OD03050

Revision History  

• Version 1.0: 2025-11-26
  Type: Initial release
  
• Version 1.1: 2026-01-14
  Changes: Database references, Structure summary
• Version 1.2: 2026-03-25
  Changes: Other, Structure summary