6GR7

Crystal Structure Of Human Transthyretin in complex with 2,4,5-trichlorophenoxyacetic acid (2,4,5-T)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.40 Å
  • R-Value Free: 0.188 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.170 

Starting Model: experimental
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This is version 1.4 of the entry. See complete history


Literature

Interspecies Variation between Fish and Human Transthyretins in Their Binding of Thyroid-Disrupting Chemicals.

Zhang, J.Grundstrom, C.Brannstrom, K.Iakovleva, I.Lindberg, M.Olofsson, A.Andersson, P.L.Sauer-Eriksson, A.E.

(2018) Environ Sci Technol 52: 11865-11874

  • DOI: https://doi.org/10.1021/acs.est.8b03581
  • Primary Citation of Related Structures:  
    6GNM, 6GNO, 6GNP, 6GNR, 6GNW, 6GON, 6GOO, 6GR7, 6GRP

  • PubMed Abstract: 

    Thyroid-disrupting chemicals (TDCs) are xenobiotics that can interfere with the endocrine system and cause adverse effects in organisms and their offspring. TDCs affect both the thyroid gland and regulatory enzymes associated with thyroid hormone homeostasis. Transthyretin (TTR) is found in the serum and cerebrospinal fluid of vertebrates, where it transports thyroid hormones. Here, we explored the interspecies variation in TDC binding to human and fish TTR (exemplified by Gilthead seabream ( Sparus aurata)). The in vitro binding experiments showed that TDCs bind with equal or weaker affinity to seabream TTR than to the human TTR, in particular, the polar TDCs (>500-fold lower affinity). Crystal structures of the seabream TTR-TDC complexes revealed that all TDCs bound at the thyroid binding sites. However, amino acid substitution of Ser117 in human TTR to Thr117 in seabream prevented polar TDCs from binding deep in the hormone binding cavity, which explains their low affinity to seabream TTR. Molecular dynamics and in silico alanine scanning simulation also suggested that the protein backbone of seabream TTR is more rigid than the human one and that Thr117 provides fewer electrostatic contributions than Ser117 to ligand binding. This provides an explanation for the weaker affinities of the ligands that rely on electrostatic interactions with Thr117. The lower affinities of TDCs to fish TTR, in particular the polar ones, could potentially lead to milder thyroid-related effects in fish.


Macromolecules
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Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Transthyretin
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
GTEx:  ENSG00000118271 
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02766
Sequence Annotations
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.40 Å
  • R-Value Free: 0.188 
  • R-Value Work: 0.169 
  • R-Value Observed: 0.170 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 42.878α = 90
b = 85.486β = 90
c = 64.488γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
XDSdata reduction
Aimlessdata scaling
PHASERphasing

Structure Validation

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Ligand Structure Quality Assessment 


Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
Swedish Research CouncilSweden--

Revision History  (Full details and data files)

  • Version 1.0: 2018-07-11
    Type: Initial release
  • Version 1.1: 2018-07-25
    Changes: Data collection, Database references
  • Version 1.2: 2018-09-26
    Changes: Data collection, Database references
  • Version 1.3: 2019-04-24
    Changes: Data collection, Database references
  • Version 1.4: 2024-01-17
    Changes: Data collection, Database references, Refinement description