Differentiating the solution structures and stability of transthyretin tetramer complexed with tolcapone and tafamidis using SEC-SWAXS and NMR

Orion Shih.

SASDXX3 – Transthyretin tetramer with over-saturated tolcapone

Transthyretin
Tolcapone
MWexperimental 64 kDa
MWexpected 56 kDa
VPorod 107 nm3
log I(s) 9.15×10-2 9.15×10-3 9.15×10-4 9.15×10-5
Transthyretin Tolcapone small angle scattering data  s, nm-1
ln I(s)
Transthyretin Tolcapone Guinier plot ln 9.15×10-2 Rg: 2.5 nm 0 (2.5 nm)-2 s2
(sRg)2I(s)/I(0)
Transthyretin Tolcapone Kratky plot 1.104 0 √3 sRg
p(r)
Transthyretin Tolcapone pair distance distribution function Rg: 2.5 nm 0 Dmax: 8.6 nm

Data validation

Fits and models

log I(s)
 s, nm-1
Transthyretin Tolcapone COOT model
Synchrotron SAXS data from solutions of transthyretin with over-saturated tolcapone in 20 mM Tris, 50 mM NaCl, pH 7 were collected on the 13A beam line at the Taiwan Photon Source, NSRRC (Hsinchu, Taiwan) using a Eiger X 1M and Eiger X 9M detector at a sample-detector distance of 0.3 m (Eiger X 1M) and 2.5 m (Eiger X 9M) and at a wavelength of λ = 0.08265 nm (I(s) vs s, where s = 4πsinθ/λ, and 2θ is the scattering angle). One solute concentration of 8.00 mg/ml was measured at 26°C. Five successive 2 second frames were collected. The data were normalized to the intensity of the transmitted beam and radially averaged; the scattering of the solvent-blank was subtracted.

Tolcapone: https://www.ebi.ac.uk/chembl/explore/compound/CHEMBL1324

Transthyretin (TTR)
Mol. type   Protein
Organism   Homo sapiens
Olig. state   Tetramer
Mon. MW   13.8 kDa
 
UniProt   P02766 (21-147)
Sequence   FASTA
 
Tolcapone
Mol. type   Other
Olig. state   Dimer
Mon. MW   0.3 kDa
Chemical formula