Crystal structure of the wild type SARS-CoV-2 papain-like protease (PLPro) with inhibitor GRL0617

Experimental Data Snapshot

  • Resolution: 2.48 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.245 
  • R-Value Observed: 0.247 

Starting Model: experimental
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This is version 1.3 of the entry. See complete history


Discovery of SARS-CoV-2 Papain-like Protease Inhibitors through a Combination of High-Throughput Screening and a FlipGFP-Based Reporter Assay.

Ma, C.Sacco, M.D.Xia, Z.Lambrinidis, G.Townsend, J.A.Hu, Y.Meng, X.Szeto, T.Ba, M.Zhang, X.Gongora, M.Zhang, F.Marty, M.T.Xiang, Y.Kolocouris, A.Chen, Y.Wang, J.

(2021) ACS Cent Sci 7: 1245-1260

  • DOI: https://doi.org/10.1021/acscentsci.1c00519
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    The papain-like protease (PL pro ) of SARS-CoV-2 is a validated antiviral drug target. Through a fluorescence resonance energy transfer-based high-throughput screening and subsequent lead optimization, we identified several PL pro inhibitors including Jun9-72-2 and Jun9-75-4 with improved enzymatic inhibition and antiviral activity compared to GRL0617 , which was reported as a SARS-CoV PL pro inhibitor. Significantly, we developed a cell-based FlipGFP assay that can be applied to predict the cellular antiviral activity of PL pro inhibitors in the BSL-2 setting. X-ray crystal structure of PL pro in complex with GRL0617 showed that binding of GRL0617 to SARS-CoV-2 induced a conformational change in the BL2 loop to a more closed conformation. Molecular dynamics simulations showed that Jun9-72-2 and Jun9-75-4 engaged in more extensive interactions than GRL0617 . Overall, the PL pro inhibitors identified in this study represent promising candidates for further development as SARS-CoV-2 antivirals, and the FlipGFP-PL pro assay is a suitable surrogate for screening PL pro inhibitors in the BSL-2 setting.

  • Organizational Affiliation

    Department of Pharmacology and Toxicology, College of Pharmacy, The University of Arizona, Tucson, Arizona 85721, United States.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Non-structural protein 3A,
B [auth J]
323Severe acute respiratory syndrome coronavirus 2Mutation(s): 0 
Find proteins for P0DTD1 (Severe acute respiratory syndrome coronavirus 2)
Explore P0DTD1 
Go to UniProtKB:  P0DTD1
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP0DTD1
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
TTT (Subject of Investigation/LOI)
Query on TTT

Download Ideal Coordinates CCD File 
C [auth A],
G [auth J]
C20 H20 N2 O
Query on SO4

Download Ideal Coordinates CCD File 
E [auth A],
F [auth A],
I [auth J],
K [auth J]
O4 S
Query on ZN

Download Ideal Coordinates CCD File 
D [auth A],
H [auth J]
Experimental Data & Validation

Experimental Data

  • Resolution: 2.48 Å
  • R-Value Free: 0.287 
  • R-Value Work: 0.245 
  • R-Value Observed: 0.247 
  • Space Group: P 1 21 1
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 46.733α = 90
b = 144.872β = 99.26
c = 60.145γ = 90
Software Package:
Software NamePurpose
HKL-2000data scaling
PDB_EXTRACTdata extraction
HKL-3000data reduction

Structure Validation

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Ligand Structure Quality Assessment 

Entry History & Funding Information

Deposition Data

Funding OrganizationLocationGrant Number
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)United StatesAI147325

Revision History  (Full details and data files)

  • Version 1.0: 2020-08-26
    Type: Initial release
  • Version 1.1: 2021-01-27
    Changes: Structure summary
  • Version 1.2: 2021-09-08
    Changes: Database references
  • Version 1.3: 2023-10-18
    Changes: Data collection, Refinement description