Crystal structure of transthyretin in complex with 3,5-diiodosalicylic acid

Experimental Data Snapshot

  • Resolution: 1.55 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.190 

wwPDB Validation   3D Report Full Report

This is version 1.2 of the entry. See complete history


Iodination of salicylic acid improves its binding to transthyretin

Gales, L.Almeida, M.R.Arsequell, G.Valencia, G.Saraiva, M.J.Damas, A.M.

(2008) Biochim Biophys Acta 1784: 512-517

  • DOI: https://doi.org/10.1016/j.bbapap.2007.11.014
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Transthyretin (TTR) is a plasma homotetrameric protein associated with senile systemic amyloidosis and familial amyloidotic polyneuropathy. In theses cases, TTR dissociation and misfolding induces the formation of amyloidogenic intermediates that assemble into toxic oligomeric species and lead to the formation of fibrils present in amyloid deposits. The four TTR monomers associate around a central hydrophobic channel where two thyroxine molecules can bind simultaneously. In each thyroxine binding site there are three pairs of symmetry related halogen binding pockets which can accommodate the four iodine substituents of thyroxine. A number of structurally diverse small molecules that bind to the TTR channel increasing the protein stability and thereafter inhibiting amyloid fibrillogenesis have been tested. In order to take advantage of the high propensity to interactions between iodine substituents and the TTR channel we have identified two iodinated derivatives of salicylic acid, 5-iodosalicylic acid and 3,5-diiodosalicylic acid, available commercially. We report in this paper the relative binding affinities of salicylic acid and the two iodinated derivatives and the crystal structure of TTR complexed with 3,5-diiodosalicylic acid, to elucidate the higher binding affinity of this compound towards TTR.

  • Organizational Affiliation

    ICBAS - Instituto de Ciências Biomédicas Abel Salazar, Largo Prof. Abel Salazar, 2, 4099-003 Porto, Portugal.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
A, B
127Homo 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
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on DIU

Download Ideal Coordinates CCD File 
C [auth A],
D [auth B]
C7 H4 I2 O3
Experimental Data & Validation

Experimental Data

  • Resolution: 1.55 Å
  • R-Value Free: 0.214 
  • R-Value Work: 0.189 
  • R-Value Observed: 0.190 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 42.539α = 90
b = 85.757β = 90
c = 64.346γ = 90
Software Package:
Software NamePurpose
DNAdata collection
MOSFLMdata reduction
SCALAdata scaling

Structure Validation

View Full Validation Report

Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2008-01-15
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance
  • Version 1.2: 2023-11-01
    Changes: Data collection, Database references, Derived calculations, Refinement description