Nuclear magnetic resonance evidence for the dimer formation of beta amyloid peptide 1-42 in 1,1,1,3,3,3-hexafluoro-2-propanol.
Anal Biochem
; 498: 59-67, 2016 Apr 01.
Article
en En
| MEDLINE
| ID: mdl-26772162
ABSTRACT
Alzheimer's disease involves accumulation of senile plaques in which filamentous aggregates of amyloid beta (Aß) peptides are deposited. Recent studies demonstrate that oligomerization pathways of Aß peptides may be complicated. To understand the mechanisms of Aß(1-42) oligomer formation in more detail, we have established a method to produce (15)N-labeled Aß(1-42) suited for nuclear magnetic resonance (NMR) studies. For physicochemical studies, the starting protein material should be solely monomeric and all Aß aggregates must be removed. Here, we succeeded in fractionating a "precipitation-resistant" fraction of Aß(1-42) from an "aggregation-prone" fraction by high-performance liquid chromatography (HPLC), even from bacterially overexpressed Aß(1-42). However, both Aß(1-42) fractions after 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) treatment formed amyloid fibrils. This indicates that the "aggregation seed" was not completely monomerized during HFIP treatment. In addition, Aß(1-42) dissolved in HFIP was found to display a monomer-dimer equilibrium, as shown by two-dimensional (1)H-(15)N NMR. We demonstrated that the initial concentration of Aß during the HFIP pretreatment altered the kinetic profiles of Aß fibril formation in a thioflavin T fluorescence assay. The findings described here should ensure reproducible results when studying the Aß(1-42) peptide.
Palabras clave
Texto completo:
1
Bases de datos:
MEDLINE
Asunto principal:
Fragmentos de Péptidos
/
Espectroscopía de Resonancia Magnética
/
Péptidos beta-Amiloides
/
Propanoles
/
Multimerización de Proteína
Idioma:
En
Revista:
Anal Biochem
Año:
2016
Tipo del documento:
Article
País de afiliación:
Japón