Merck
  • Home
  • Search Results
  • Considerably Unfolded Transthyretin Monomers Preceed and Exchange with Dynamically Structured Amyloid Protofibrils.

Considerably Unfolded Transthyretin Monomers Preceed and Exchange with Dynamically Structured Amyloid Protofibrils.

Scientific reports (2015-06-26)
Minna Groenning, Raul I Campos, Daniel Hirschberg, Per Hammarström, Bente Vestergaard
ABSTRACT

Despite numerous studies, a detailed description of the transthyretin (TTR) self-assembly mechanism and fibril structure in TTR amyloidoses remains unresolved. Here, using a combination of primarily small -angle X-ray scattering (SAXS) and hydrogen exchange mass spectrometry (HXMS) analysis, we describe an unexpectedly dynamic TTR protofibril structure which exchanges protomers with highly unfolded monomers in solution. The protofibrils only grow to an approximate final size of 2,900 kDa and a length of 70 nm and a comparative HXMS analysis of native and aggregated samples revealed a much higher average solvent exposure of TTR upon fibrillation. With SAXS, we reveal the continuous presence of a considerably unfolded TTR monomer throughout the fibrillation process, and show that a considerable fraction of the fibrillating protein remains in solution even at a late maturation state. Together, these data reveal that the fibrillar state interchanges with the solution state. Accordingly, we suggest that TTR fibrillation proceeds via addition of considerably unfolded monomers, and the continuous presence of amyloidogenic structures near the protofibril surface offers a plausible explanation for secondary nucleation. We argue that the presence of such dynamic structural equilibria must impact future therapeutic development strategies.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Acetonitrile, for DNA synthesis
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D, contains 0.05 wt. % 3-(trimethylsilyl)propionic-2,2,3,3-d4 acid, sodium salt
Sigma-Aldrich
Deuterium oxide, 99 atom % D
Sigma-Aldrich
Acetonitrile, electronic grade, 99.999% trace metals basis
Sigma-Aldrich
Ultrapure Acetonitrile
Sigma-Aldrich
Deuterium oxide, "100%", 99.990 atom % D
Sigma-Aldrich
Acetonitrile, anhydrous, 99.8%
Sigma-Aldrich
Deuterium oxide, standard, 99.98 atom %±0.01 atom % D
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D, contains 1 % (w/w) 3-(trimethylsilyl)-1-propanesulfonic acid, sodium salt (DSS)
Sigma-Aldrich
Acetonitrile, Preparateur, ≥99.9% (GC), Customized plastic drum
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D, contains 0.75 wt. % 3-(trimethylsilyl)propionic-2,2,3,3-d4 acid, sodium salt
Sigma-Aldrich
Deuterium oxide, 99.8 atom % D
Sigma-Aldrich
Deuterium oxide, extra, 99.994 atom % D
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D, glass distilled
Sigma-Aldrich
Acetonitrile, Preparateur, ≥99.9% (GC), One-time steel-plastic (SP) drum
Sigma-Aldrich
Deuterium oxide, filtered, 99.8 atom % D
Sigma-Aldrich
Deuterium oxide, 60 atom % D
Sigma-Aldrich
Deuterium oxide, 70 atom % D
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D
Sigma-Aldrich
Deuterium oxide, "100%", ≥99.96 atom % D
Sigma-Aldrich
Acetonitrile solution, contains 0.1 % (v/v) trifluoroacetic acid, suitable for HPLC
Sigma-Aldrich
Acetonitrile solution, contains 0.05 % (v/v) trifluoroacetic acid
Millipore
Acetonitrile solution, suitable for HPLC, acetonitrile:water 5:95% (v/v), 10 mM Ammoniumbicarbonate, pH 10,0