9HH5 | pdb_00009hh5

Crystal Structure of nsp15 Endoribonuclease from SARS CoV-2 in Complex with Sepantronium (YM-155)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.08 Å
  • R-Value Free: 
    0.205 (Depositor), 0.210 (DCC) 
  • R-Value Work: 
    0.191 (Depositor), 0.197 (DCC) 
  • R-Value Observed: 
    0.192 (Depositor) 

Starting Model: experimental
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Ligand Structure Quality Assessment 


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Literature

Identification, validation, and characterization of approved and investigational drugs interfering with the SARS-CoV-2 endoribonuclease Nsp15.

Chatziefthymiou, S.D.Kuzikov, M.Afandi, S.Kovacs, G.Srivastava, S.Zaliani, A.Gruzinov, A.Pompidor, G.Lunelli, M.Ahmed, G.R.Labahn, J.Hakanpaa, J.Windshugel, B.Kolbe, M.

(2025) Protein Sci 34: e70156-e70156

  • DOI: https://doi.org/10.1002/pro.70156
  • Primary Citation of Related Structures:  
    9HH5, 9HH6

  • PubMed Abstract: 

    Since the emergence of SARS-CoV-2 at the end of 2019, the virus has caused significant global health and economic disruptions. Despite the rapid development of antiviral vaccines and some approved treatments such as remdesivir and paxlovid, effective antiviral pharmacological treatments for COVID-19 patients remain limited. This study explores Nsp15, a 3'-uridylate-specific RNA endonuclease, which has a critical role in immune system evasion and hence in escaping the innate immune sensors. We conducted a comprehensive drug repurposing screen and identified 44 compounds that showed more than 55% inhibition of Nsp15 activity in a real-time fluorescence assay. A validation pipeline was employed to exclude unspecific interactions, and dose-response assays confirmed 29 compounds with an IC 50 below 10 μM. Structural studies, including molecular docking and x-ray crystallography, revealed key interactions of identified inhibitors, such as TAS-103 and YM-155, with the Nsp15 active site and other critical regions. Our findings show that the identified compounds, particularly those retaining potency under different assay conditions, could serve as promising hits for developing Nsp15 inhibitors. Additionally, the study emphasizes the potential of combination therapies targeting multiple viral processes to enhance treatment efficacy and reduce the risk of drug resistance. This research contributes to the ongoing efforts to develop effective antiviral therapies for SARS-CoV-2 and possibly other coronaviruses.


  • Organizational Affiliation

    Photon Science, DESY, Hamburg, Germany.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Replicase polyprotein 1ab346Severe acute respiratory syndrome coronavirus 2Mutation(s): 0 
Gene Names: ORF1ab
UniProt
Find proteins for A0A8B1IYC0 (Severe acute respiratory syndrome coronavirus 2)
Explore A0A8B1IYC0 
Go to UniProtKB:  A0A8B1IYC0
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A8B1IYC0
Sequence Annotations
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  • Reference Sequence
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 2
MoleculeChains Sequence LengthOrganismDetailsImage
Nsp15 - Uridylate-specific endoribonuclease268Severe acute respiratory syndrome coronavirus 2Mutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
Expand
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.08 Å
  • R-Value Free:  0.205 (Depositor), 0.210 (DCC) 
  • R-Value Work:  0.191 (Depositor), 0.197 (DCC) 
  • R-Value Observed: 0.192 (Depositor) 
Space Group: P 63
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 151.408α = 90
b = 151.408β = 90
c = 109.302γ = 120
Software Package:
Software NamePurpose
REFMACrefinement
XDSdata reduction
Aimlessdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Other governmentGermanyDESY Strategy Fund

Revision History  (Full details and data files)

  • Version 1.0: 2025-05-28
    Type: Initial release