9SQK | pdb_00009sqk

Crystal structure hASF1A 156-cr17


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free: 
    0.211 (Depositor), 0.210 (DCC) 
  • R-Value Work: 
    0.179 (Depositor), 0.178 (DCC) 
  • R-Value Observed: 
    0.180 (Depositor) 

Starting Model: experimental
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wwPDB Validation 3D Report Full Report

Validation slider image for 9SQK

This is version 1.0 of the entry. See complete history

Literature

Downsizing the Histone H3-H4 Quaternary Structure Into Foldamer Mimetics Yields High-Affinity and Cell-Permeable Ligands of ASF1.

Li, B.Perrin, M.E.Maillard, E.Vitard, A.Moal, G.Mbianda, J.Andre, C.Teixeira Nunes, M.Vandamme, M.Pinna, G.Douat, C.Thinon, E.Guerois, R.Legrand, P.Guichard, G.Ochsenbein, F.

(2026) Angew Chem Int Ed Engl : e4112426-e4112426

  • DOI: https://doi.org/10.1002/anie.4112426
  • Primary Citation Related Structures: 
    9SQK, 9SS3, 9SVO, 9TRB

  • PubMed Abstract: 

    Mimicking complex protein-protein interfaces with small, well-defined molecular scaffolds remains a major challenge in chemical biology. Here, we report a foldamer-based downsizing strategy that compresses the quaternary architecture of the histone H3-H4 dimer into compact peptide-oligourea hybrids acting as high-affinity ligands of the histone chaperone Anti-Silencing Function 1 (ASF1). Guided by multiple high-resolution co-crystal structures, we designed a series of foldamer mimetics that accurately reproduce both the H3 α-helix and the H4 β-strand epitopes. Systematic optimization of linker geometry, β-strand mimicry, formal charge, and selective backbone N-methylation yielded highly stable ligands with nanomolar affinities, enhanced proteolytic resistance, and robust cytosolic penetration. Notably, the optimized constructs and their N-methylated analogues recapitulate the binding mode of the native H3-H4 dimer on ASF1 with high fidelity and engage endogenous ASF1 in cell extracts, demonstrating effective intracellular target recognition. Together, these results show that peptide-oligourea foldamers can reproduce the structural features of a protein quaternary structure surface, combining high affinity, high stability and cell permeability.


  • Organizational Affiliation
    • Univ. Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, IECB, F-33600, Pessac, France.

Macromolecule Content 

  • Total Structure Weight: 81.11 kDa 
  • Atom Count: 6,889 
  • Modeled Residue Count: 687 
  • Deposited Residue Count: 700 
  • Unique protein chains: 2

Macromolecules

Find similar proteins by:|  3D Structure
Entity ID: 1
MoleculeChains  Sequence LengthOrganismDetailsImage
Histone chaperone ASF1A
A, B, C, D
157Homo sapiensMutation(s): 0 
Gene Names: ASF1ACGI-98HSPC146
UniProt & NIH Common Fund Data Resources
Find proteins for Q9Y294 (Homo sapiens)
Explore Q9Y294 
Go to UniProtKB:  Q9Y294
PHAROS:  Q9Y294
GTEx:  ENSG00000111875 
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupQ9Y294
Sequence Annotations
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Reference Sequence
Find similar proteins by:  Sequence   |   3D Structure  
Entity ID: 2
MoleculeChains  Sequence LengthOrganismDetailsImage
cr17
E, F, G, H
18Homo sapiensMutation(s): 0 
Entity Groups
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
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Reference Sequence

Small Molecules

Ligands 6 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
P6G

Query on P6G



Download:Ideal Coordinates CCD File
M [auth C]HEXAETHYLENE GLYCOL
C12 H26 O7
IIRDTKBZINWQAW-UHFFFAOYSA-N
1PE

Query on 1PE



Download:Ideal Coordinates CCD File
K [auth B]PENTAETHYLENE GLYCOL
C10 H22 O6
JLFNLZLINWHATN-UHFFFAOYSA-N
PGE

Query on PGE



Download:Ideal Coordinates CCD File
J [auth A],
N [auth C]
TRIETHYLENE GLYCOL
C6 H14 O4
ZIBGPFATKBEMQZ-UHFFFAOYSA-N
PEG

Query on PEG



Download:Ideal Coordinates CCD File
P [auth D]DI(HYDROXYETHYL)ETHER
C4 H10 O3
MTHSVFCYNBDYFN-UHFFFAOYSA-N
GOL

Query on GOL



Download:Ideal Coordinates CCD File
I [auth A],
L [auth B]
GLYCEROL
C3 H8 O3
PEDCQBHIVMGVHV-UHFFFAOYSA-N
CL

Query on CL



Download:Ideal Coordinates CCD File
O [auth D]CHLORIDE ION
Cl
VEXZGXHMUGYJMC-UHFFFAOYSA-M
Modified Residues  4 Unique
IDChains TypeFormula2D DiagramParent
0W6
Query on 0W6
E, F, G, H
L-PEPTIDE LINKINGC5 H11 N O2

--

A1ICL
Query on A1ICL
E, F, G, H
PEPTIDE LINKINGC4 H10 N2 O2

--

N0A
Query on N0A
E, F, G, H
L-PEPTIDE LINKINGC9 H10 F N O2PHE
QQB
Query on QQB
E, F, G, H
L-PEPTIDE LINKINGC14 H16 N2 O2

--

Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.70 Å
  • R-Value Free:  0.211 (Depositor), 0.210 (DCC) 
  • R-Value Work:  0.179 (Depositor), 0.178 (DCC) 
  • R-Value Observed: 0.180 (Depositor) 
Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 59.574α = 90
b = 114.094β = 90
c = 115.674γ = 90
Software Package:
Software NamePurpose
BUSTERrefinement
XDSdata reduction
XDSdata scaling
STARANISOdata scaling
MOLREPphasing

Structure Validation

View Full Validation Report



Entry History 

& Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
French Alternative Energies and Atomic Energy Commission (CEA)France--
Agence Nationale de la Recherche (ANR)FranceANR-20-CE18-0038

Revision History  (Full details and data files)

  • Version 1.0: 2026-09-02
    Type: Initial release