Lactam cyclised mimetic of a fragment of p21

Experimental Data Snapshot

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

wwPDB Validation   3D Report Full Report

This is version 1.3 of the entry. See complete history


Rational Design of a 310-Helical PIP-Box Mimetic Targeting PCNA, the Human Sliding Clamp.

Wegener, K.L.McGrath, A.E.Dixon, N.E.Oakley, A.J.Scanlon, D.B.Abell, A.D.Bruning, J.B.

(2018) Chemistry 24: 11325-11331

  • DOI: https://doi.org/10.1002/chem.201801734
  • Primary Citation of Related Structures:  
    6CBI, 6CEJ, 6CIV, 6CIX

  • PubMed Abstract: 

    The human sliding clamp (PCNA) controls access to DNA for many proteins involved in DNA replication and repair. Proteins are recruited to the PCNA surface by means of a short, conserved peptide motif known as the PCNA-interacting protein box (PIP-box). Inhibitors of these essential protein-protein interactions may be useful as cancer therapeutics by disrupting DNA replication and repair in these highly proliferative cells. PIP-box peptide mimetics have been identified as a potentially rapid route to potent PCNA inhibitors. Here we describe the rational design and synthesis of the first PCNA peptidomimetic ligands, based on the high affinity PIP-box sequence from the natural PCNA inhibitor p21. These mimetics incorporate covalent i,i+4 side-chain/side-chain lactam linkages of different lengths, designed to constrain the peptides into the 3 10 -helical structure required for PCNA binding. NMR studies confirmed that while the unmodified p21 peptide had little defined structure in solution, mimetic ACR2 pre-organized into 3 10 -helical structure prior to interaction with PCNA. ACR2 displayed higher affinity binding than most known PIP-box peptides, and retains the native PCNA binding mode, as observed in the co-crystal structure of ACR2 bound to PCNA. This study offers a promising new strategy for PCNA inhibitor design for use as anti-cancer therapeutics.

  • Organizational Affiliation

    Institute for Photonics and Advanced Sensing (IPAS), School of Biological Sciences, The University of Adelaide, South Australia, 5005, Australia.


Find similar proteins by:  Sequence   |   3D Structure  

Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
p21A [auth C]14Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P38936 (Homo sapiens)
Explore P38936 
Go to UniProtKB:  P38936
PHAROS:  P38936
GTEx:  ENSG00000124762 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP38936
Sequence Annotations
  • Reference Sequence
Small Molecules
Modified Residues  1 Unique
IDChains TypeFormula2D DiagramParent
Query on DAB
Experimental Data & Validation

Experimental Data

  • Method: SOLUTION NMR
  • Conformers Calculated: 100 
  • Conformers Submitted: 20 
  • Selection Criteria: structures with the lowest energy 

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2018-07-04
    Type: Initial release
  • Version 1.1: 2018-08-01
    Changes: Data collection, Database references
  • Version 1.2: 2018-08-29
    Changes: Data collection, Database references
  • Version 1.3: 2023-06-14
    Changes: Database references, Other