6FXU

Crystal structure of human transthyretin mutant T119M at pH 5.5


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 1.36 Å
  • R-Value Free: 0.216 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.193 

Starting Model: experimental
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This is version 1.2 of the entry. See complete history


Literature

Disease-associated mutations impacting BC-loop flexibility trigger long-range transthyretin tetramer destabilization and aggregation.

Esperante, S.A.Varejao, N.Pinheiro, F.Sant'Anna, R.Luque-Ortega, J.R.Alfonso, C.Sora, V.Papaleo, E.Rivas, G.Reverter, D.Ventura, S.

(2021) J Biol Chem 297: 101039-101039

  • DOI: https://doi.org/10.1016/j.jbc.2021.101039
  • Primary Citation of Related Structures:  
    6FWD, 6FXU, 6FZL

  • PubMed Abstract: 

    Hereditary transthyretin amyloidosis (ATTR) is an autosomal dominant disease characterized by the extracellular deposition of the transport protein transthyretin (TTR) as amyloid fibrils. Despite the progress achieved in recent years, understanding why different TTR residue substitutions lead to different clinical manifestations remains elusive. Here, we studied the molecular basis of disease-causing missense mutations affecting residues R34 and K35. R34G and K35T variants cause vitreous amyloidosis, whereas R34T and K35N mutations result in amyloid polyneuropathy and restrictive cardiomyopathy. All variants are more sensitive to pH-induced dissociation and amyloid formation than the wild-type (WT)-TTR counterpart, specifically in the variants deposited in the eyes amyloid formation occurs close to physiological pHs. Chemical denaturation experiments indicate that all the mutants are less stable than WT-TTR, with the vitreous amyloidosis variants, R34G and K35T, being highly destabilized. Sequence-induced stabilization of the dimer-dimer interface with T119M rendered tetramers containing R34G or K35T mutations resistant to pH-induced aggregation. Because R34 and K35 are among the residues more distant to the TTR interface, their impact in this region is therefore theorized to occur at long range. The crystal structures of double mutants, R34G/T119M and K35T/T119M, together with molecular dynamics simulations indicate that their strong destabilizing effect is initiated locally at the BC loop, increasing its flexibility in a mutation-dependent manner. Overall, the present findings help us to understand the sequence-dynamic-structural mechanistic details of TTR amyloid aggregation triggered by R34 and K35 variants and to link the degree of mutation-induced conformational flexibility to protein aggregation propensity.


  • Organizational Affiliation

    Institut de Biotecnologia i de Biomedicina and Departament de Bioquímica i de Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Barcelona, Spain. Electronic address: sesperante@infant.org.ar.


Macromolecules
Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Transthyretin
A, B
127Homo sapiensMutation(s): 1 
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: 1.36 Å
  • R-Value Free: 0.216 
  • R-Value Work: 0.192 
  • R-Value Observed: 0.193 
  • Space Group: P 21 21 2
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 86.075α = 90
b = 43.183β = 90
c = 63.834γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
Aimlessdata scaling
PDB_EXTRACTdata extraction
XDSdata reduction
PHASERphasing

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2019-03-20
    Type: Initial release
  • Version 1.1: 2023-04-12
    Changes: Database references
  • Version 1.2: 2024-02-07
    Changes: Data collection, Refinement description