9NHU | pdb_00009nhu

Structure of SARS-CoV-2 NSP14 bound to 5-(((cyclopropylmethyl)amino)methyl)-N-((4-cyclopropylthiazol-2-yl)methyl)-1H-pyrazole-3-carboxamide


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free: 
    0.272 (Depositor), 0.273 (DCC) 
  • R-Value Work: 
    0.232 (Depositor), 0.232 (DCC) 
  • R-Value Observed: 
    0.234 (Depositor) 

Starting Model: experimental
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wwPDB Validation 3D Report Full Report

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Ligand Structure Quality Assessment 


This is version 1.2 of the entry. See complete history

Literature

Fragment-Based Development of NSP14 Exonuclease Inhibitors Confounded by Batch-to-Batch Variability.

Coker, J.A.Sun, R.Polzer, P.M.Romigh, T.Goins, C.M.Wang, N.S.Jung, J.U.Stauffer, S.R.

(2026) ACS Chem Biol 21: 413-418

  • DOI: https://doi.org/10.1021/acschembio.5c00930
  • Primary Citation Related Structures: 
    9NAZ, 9NFP, 9NHA, 9NHU, 9NIO, 9NJG

  • PubMed Abstract: 

    Point mutations in the exonuclease (ExoN) site of nonstructural protein 14 (NSP14) compromise the fitness of betacoronaviruses such as SARS-CoV-2, implicating NSP14 ExoN inhibition as an antiviral strategy. However, there are no advanced compounds that inhibit NSP14's ExoN activity. Building upon the reported crystal structures of two fragments bound to NSP14's ExoN site, we identified a series of 3,5-disubsituted pyrazoles that bound to and inhibited NSP14 ExoN. However, upon resynthesis, we discovered that these putative leads were false positives, perhaps due to contaminating divalent cations, which potently inhibit NSP14 ExoN. Our results provide a cautionary tale to the field about the sensitivity of NSP14 to divalent cations and illustrate the challenges associated with directly targeting the NSP14 ExoN site via fragment merging.


  • Organizational Affiliation
    • Cleveland Clinic Center for Therapeutics Discovery, Cleveland Clinic Research, Cleveland, Ohio 44106, United States.

Macromolecule Content 

  • Total Structure Weight: 60.25 kDa 
  • Atom Count: 3,518 
  • Modeled Residue Count: 423 
  • Deposited Residue Count: 523 
  • Unique protein chains: 1

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
Guanine-N7 methyltransferase nsp14523Severe acute respiratory syndrome coronavirus 2Mutation(s): 0 
Gene Names: rep1a-1b
EC: 2.1.1.56 (PDB Primary Data), 3.1.13 (PDB Primary Data)
UniProt
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
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Reference Sequence

Small Molecules

Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
A1BYF
(Subject of Investigation/LOI)

Query on A1BYF



Download:Ideal Coordinates CCD File
G [auth A]5-{[(cyclopropylmethyl)amino]methyl}-N-[(4-cyclopropyl-1,3-thiazol-2-yl)methyl]-1H-pyrazole-3-carboxamide
C16 H21 N5 O S
SFATUIRQTKFPPJ-UHFFFAOYSA-N
PO4

Query on PO4



Download:Ideal Coordinates CCD File
E [auth A],
F [auth A]
PHOSPHATE ION
O4 P
NBIIXXVUZAFLBC-UHFFFAOYSA-K
ZN

Query on ZN



Download:Ideal Coordinates CCD File
B [auth A],
C [auth A],
D [auth A]
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.10 Å
  • R-Value Free:  0.272 (Depositor), 0.273 (DCC) 
  • R-Value Work:  0.232 (Depositor), 0.232 (DCC) 
  • R-Value Observed: 0.234 (Depositor) 
Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 67.79α = 90
b = 68.216β = 90
c = 137.873γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
xia2data reduction
DIALSdata scaling
PHASERphasing

Structure Validation

View Full Validation Report



Ligand Structure Quality Assessment 


Entry History 

& Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Not funded--

Revision History  (Full details and data files)

  • Version 1.0: 2025-12-03
    Type: Initial release
  • Version 1.1: 2026-03-04
    Changes: Database references
  • Version 1.2: 2026-04-01
    Changes: Database references