4AC4

CRYSTAL STRUCTURE OF TRANSTHYRETIN IN COMPLEX WITH LIGAND C-18


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.219 
  • R-Value Observed: 0.222 

Starting Model: experimental
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This is version 1.6 of the entry. See complete history


Literature

Crystallographic Study of Novel Transthyretin Ligands Exhibiting Negative-Cooperativity between Two Thyroxine Binding Sites.

Tomar, D.Khan, T.Singh, R.R.Mishra, S.Gupta, S.Surolia, A.Salunke, D.M.

(2012) PLoS One 7: 43522

  • DOI: https://doi.org/10.1371/journal.pone.0043522
  • Primary Citation of Related Structures:  
    4ABQ, 4ABU, 4ABV, 4ABW, 4AC2, 4AC4, 4ANK

  • PubMed Abstract: 

    Transthyretin (TTR) is a homotetrameric serum and cerebrospinal fluid protein that transports thyroxine (T4) and retinol by binding to retinol binding protein. Rate-limiting tetramer dissociation and rapid monomer misfolding and disassembly of TTR lead to amyloid fibril formation in different tissues causing various amyloid diseases. Based on the current understanding of the pathogenesis of TTR amyloidosis, it is considered that the inhibition of amyloid fibril formation by stabilization of TTR in native tetrameric form is a viable approach for the treatment of TTR amyloidosis. We have examined interactions of the wtTTR with a series of compounds containing various substitutions at biphenyl ether skeleton and a novel compound, previously evaluated for binding and inhibiting tetramer dissociation, by x-ray crystallographic approach. High resolution crystal structures of five ligands in complex with wtTTR provided snapshots of negatively cooperative binding of ligands in two T4 binding sites besides characterizing their binding orientations, conformations, and interactions with binding site residues. In all complexes, the ligand has better fit and more potent interactions in first T4 site i.e. (AC site) than the second T4 site (BD site). Together, these results suggest that AC site is a preferred ligand binding site and retention of ordered water molecules between the dimer interfaces further stabilizes the tetramer by bridging a hydrogen bond interaction between Ser117 and its symmetric copy. Novel biphenyl ether based compounds exhibit negative-cooperativity while binding to two T4 sites which suggests that binding of only single ligand molecule is sufficient to inhibit the TTR tetramer dissociation.


  • Organizational Affiliation

    Structural Biology Unit, National Institute of Immunology, New Delhi, India.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
TRANSTHYRETIN
A, B
127Homo sapiensMutation(s): 0 
UniProt & NIH Common Fund Data Resources
Find proteins for P02766 (Homo sapiens)
Explore P02766 
Go to UniProtKB:  P02766
PHAROS:  P02766
GTEx:  ENSG00000118271 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02766
Sequence Annotations
Expand
  • Reference Sequence
Small Molecules
Binding Affinity Annotations 
IDSourceBinding Affinity
HKA BindingDB:  4AC4 IC50: 4.10e+4 (nM) from 1 assay(s)
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.80 Å
  • R-Value Free: 0.258 
  • R-Value Work: 0.219 
  • R-Value Observed: 0.222 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 85.33α = 90
b = 42.86β = 90
c = 64.28γ = 90
Software Package:
Software NamePurpose
REFMACrefinement
MOSFLMdata reduction
SCALAdata scaling
MOLREPphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2012-12-26
    Type: Initial release
  • Version 1.1: 2014-10-29
    Changes: Database references
  • Version 1.2: 2015-04-01
    Changes: Database references
  • Version 1.3: 2019-01-30
    Changes: Data collection, Derived calculations, Experimental preparation, Other
  • Version 1.4: 2019-02-06
    Changes: Data collection, Experimental preparation
  • Version 1.5: 2019-07-17
    Changes: Data collection, Derived calculations
  • Version 1.6: 2023-12-20
    Changes: Data collection, Database references, Derived calculations, Other, Refinement description