Crystal structure of human Transthyretin with bound iodide

Experimental Data Snapshot

  • Resolution: 1.80 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.204 

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The effect of iodide and chloride on transthyretin structure and stability

Hornberg, A.Hultdin, U.W.Olofsson, A.Sauer-Eriksson, A.E.

(2005) Biochemistry 44: 9290-9299

  • DOI: https://doi.org/10.1021/bi050249z
  • Primary Citation of Related Structures:  
    1ZCR, 1ZD6

  • PubMed Abstract: 

    Transthyretin amyloid formation occurs through a process of tetramer destabilization and partial unfolding. Small molecules, including the natural ligand thyroxine, stabilize the tetrameric form of the protein, and serve as inhibitors of amyloid formation. Crucial for TTR's ligand-binding properties are its three halogen-binding sites situated at the hormone-binding channel. In this study, we have performed a structural characterization of the binding of two halides, iodide and chloride, to TTR. Chlorides are known to shield charge repulsions at the tetrameric interface of TTR, which improve tetramer stability of the protein. Our study shows that iodides, like chlorides, provide tetramer stabilization in a concentration-dependent manner and at concentrations approximately 15-fold below that of chlorides. To elucidate binding sites of the halides, we took advantage of the anomalous scattering of iodide and used the single-wavelength anomalous dispersion (SAD) method to solve the iodide-bound TTR structure at 1.8 A resolution. The structure of chloride-bound TTR was determined at 1.9 A resolution using difference Fourier techniques. The refined structures showed iodides and chlorides bound at two of the three halogen-binding sites located at the hydrophobic channel. These sites therefore also function as halide-binding sites.

  • Organizational Affiliation

    Umeå Centre for Molecular Pathogenesis, Umeå University, SE-901 87 Umeå, Sweden.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
128Homo sapiensMutation(s): 0 
Gene Names: TTRPALB
UniProt & NIH Common Fund Data Resources
Find proteins for P02766 (Homo sapiens)
Explore P02766 
Go to UniProtKB:  P02766
PHAROS:  P02766
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02766
Sequence Annotations
  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Resolution: 1.80 Å
  • R-Value Free: 0.238 
  • R-Value Work: 0.203 
  • R-Value Observed: 0.204 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 43.38α = 90
b = 86.26β = 90
c = 64.44γ = 90
Software Package:
Software NamePurpose
DENZOdata reduction
SCALEPACKdata scaling

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2005-07-12
    Type: Initial release
  • Version 1.1: 2008-04-30
    Changes: Version format compliance
  • Version 1.2: 2011-07-13
    Changes: Advisory, Derived calculations, Version format compliance