Crystal structure of the de novo designed fluorinated peptide alpha4F3d

Experimental Data Snapshot

  • Resolution: 1.19 Å
  • R-Value Free: 0.187 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.178 

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This is version 1.2 of the entry. See complete history


Comparison of the structures and stabilities of coiled-coil proteins containing hexafluoroleucine and t-butylalanine provides insight into the stabilizing effects of highly fluorinated amino acid side-chains.

Buer, B.C.Meagher, J.L.Stuckey, J.A.Marsh, E.N.

(2012) Protein Sci 21: 1705-1715

  • DOI: https://doi.org/10.1002/pro.2150
  • Primary Citation of Related Structures:  
    4G3B, 4G4L, 4G4M

  • PubMed Abstract: 

    Highly fluorinated analogs of hydrophobic amino acids are well known to increase the stability of proteins toward thermal unfolding and chemical denaturation, but there is very little data on the structural consequences of fluorination. We have determined the structures and folding energies of three variants of a de novo designed 4-helix bundle protein whose hydrophobic cores contain either hexafluoroleucine (hFLeu) or t-butylalanine (tBAla). Although the buried hydrophobic surface area is the same for all three proteins, the incorporation of tBAla causes a rearrangement of the core packing, resulting in the formation of a destabilizing hydrophobic cavity at the center of the protein. In contrast, incorporation of hFLeu, causes no changes in core packing with respect to the structure of the nonfluorinated parent protein which contains only leucine in the core. These results support the idea that fluorinated residues are especially effective at stabilizing proteins because they closely mimic the shape of the natural residues they replace while increasing buried hydrophobic surface area.

  • Organizational Affiliation

    Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
26N/AMutation(s): 0 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on ACE

Download Ideal Coordinates CCD File 
C2 H4 O
Experimental Data & Validation

Experimental Data

  • Resolution: 1.19 Å
  • R-Value Free: 0.187 
  • R-Value Work: 0.178 
  • R-Value Observed: 0.178 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 30.819α = 90
b = 39.251β = 90
c = 41.233γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling
PDB_EXTRACTdata extraction
MD2data collection
HKL-2000data reduction
HKL-2000data scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-10-31
    Type: Initial release
  • Version 1.1: 2012-11-21
    Changes: Database references
  • Version 1.2: 2017-11-15
    Changes: Refinement description