9QRL | pdb_00009qrl

DNA polymerase with inhibitor #2


Experimental Data Snapshot

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.20 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 

Starting Model: in silico
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wwPDB Validation 3D Report Full Report

Validation slider image for 9QRL

This is version 1.2 of the entry. See complete history

Literature

A unique inhibitor conformation selectively targets the DNA polymerase PolC of Gram-positive priority pathogens.

Urem, M.Friggen, A.H.Musch, N.Silverman, M.H.Swain, C.J.Barbachyn, M.R.Mortin, L.I.Yu, X.DeLuccia, R.J.Lamers, M.H.Smits, W.K.

(2025) Nat Commun 16: 9784-9784

  • DOI: https://doi.org/10.1038/s41467-025-65324-8
  • Primary Citation Related Structures: 
    9QPC, 9QRL, 9QRN

  • PubMed Abstract: 

    Infections with antimicrobial resistant pathogens are a major threat to human health. Inhibitors of the replicative polymerase PolC are a promising novel class of antimicrobials against Gram-positive pathogens, but the structural basis for their activity remains unknown. The first-in-class PolC-targeting antimicrobial, ibezapolstat, is a guanine analogue in late-stage clinical development for the treatment of Clostridioides difficile infections, and related inhibitors are being developed for systemic treatment of infections with methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). Here, we present the cryo-electron microscopy structures of Enterococcus faecium PolC bound to DNA and in complex with ibezapolstat or the previously-undescribed inhibitor ACX-801. Both inhibitors form base-pairing interactions with the DNA in the active site, thereby competing with incoming dGTP nucleotides. We identify a crucial susceptibility determinant in PolC that is conserved in other organisms, such as C. difficile. This is explained by an unusual non-planar conformation of the inhibitors that induce a binding pocket in PolC. By combining structural, biochemical, bioinformatic and genetic analyses, this work lays the foundation for the rational development of an innovative class of antimicrobials against Gram-positive priority pathogens.


  • Organizational Affiliation
    • Leiden University Center of Infectious Diseases (LUCID), Leiden University Medical Center, Leiden, The Netherlands.

Macromolecule Content 

  • Total Structure Weight: 191.12 kDa 
  • Atom Count: 9,140 
  • Modeled Residue Count: 1,117 
  • Deposited Residue Count: 1,552 
  • Unique protein chains: 1
  • Unique nucleic acid chains: 3

Macromolecules


Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
DNA polymerase III PolC-type1,474Enterococcus faeciumMutation(s): 2 
Gene Names: polCM3X98_02600
EC: 2.7.7.7
UniProt
Find proteins for A0A9X4B319 (Enterococcus faecium)
Explore A0A9X4B319 
Go to UniProtKB:  A0A9X4B319
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupA0A9X4B319
Sequence Annotations
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Reference Sequence
Find similar nucleic acids by:  Sequence
Entity ID: 2
MoleculeChains LengthOrganismImage
DNA (5'-D(P*TP*AP*A)-3')B [auth E]3Escherichia coli
Sequence Annotations
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Reference Sequence
Find similar nucleic acids by:  (by identity cutoff) 
Entity ID: 3
MoleculeChains LengthOrganismImage
DNA (5'-D(P*GP*GP*TP*GP*CP*GP*CP*AP*T)-3')C [auth P]33Escherichia coli
Sequence Annotations
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Reference Sequence
Find similar nucleic acids by:  (by identity cutoff) 
Entity ID: 4
MoleculeChains LengthOrganismImage
DNA (5'-D(P*CP*CP*AP*TP*GP*CP*GP*CP*AP*CP*C)-3')D [auth T]42Escherichia coli
Sequence Annotations
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Reference Sequence

Small Molecules

Ligands 3 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
A1I9T
(Subject of Investigation/LOI)

Query on A1I9T



Download:Ideal Coordinates CCD File
K [auth T]Ibezapolstat
C18 H20 Cl2 N6 O2
DEGSGBKTODESHH-UHFFFAOYSA-N
ZN

Query on ZN



Download:Ideal Coordinates CCD File
E [auth A],
F [auth A],
G [auth A],
H [auth A]
ZINC ION
Zn
PTFCDOFLOPIGGS-UHFFFAOYSA-N
MG

Query on MG



Download:Ideal Coordinates CCD File
I [auth A],
J [auth A]
MAGNESIUM ION
Mg
JLVVSXFLKOJNIY-UHFFFAOYSA-N

Experimental Data & Validation

Experimental Data

  • Method: ELECTRON MICROSCOPY
  • Resolution: 3.20 Å
  • Aggregation State: PARTICLE 
  • Reconstruction Method: SINGLE PARTICLE 
EM Software:
TaskSoftware PackageVersion
MODEL REFINEMENTPHENIX1.18.2

Structure Validation

View Full Validation Report



Entry History 

& Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Other governmentNetherlandsPOLSTOP2

Revision History  (Full details and data files)

  • Version 1.0: 2025-09-24
    Type: Initial release
  • Version 1.1: 2025-12-03
    Changes: Data collection, Derived calculations, Structure summary
  • Version 1.2: 2026-04-08
    Changes: Data collection, Database references