Amide solvent protection analysis demonstrates that amyloid-beta(1-40) and amyloid-beta(1-42) form different fibrillar structures under identical conditions.
2007 (English)In: Biochem J, ISSN 1470-8728, Vol. 404, no 1, 63-70 p.Article in journal (Refereed) Published
AD (Alzheimer's disease) is a neurodegenerative disorder characterized by self-assembly and amyloid formation of the 39–43 residue long Ab (amyloid-b)-peptide. The most abundant species, Ab(1–40) and Ab(1–42), are both present within senile plaques, but Ab(1–42) peptides are considerably more prone to self-aggregation and are also essential for the development of AD. To understand the molecular and pathological mechanisms behind AD, a detailed knowledge of the amyloid structures of Ab-peptides is vital. In the present study we have used quenched hydrogen/deuterium-exchange NMR experiments to probe the structure of Ab(1–40) fibrils. The fibrils were prepared and analysed identically as in our previous study on Ab(1–42) fibrils, allowing a direct comparison of the two fibrillar structures. The solvent protection pattern of Ab(1–40) fibrils revealed two well-protected regions, consistent with a structural arrangement of two b-strands connected with a bend. This protection pattern partly resembles the pattern found in Ab(1–42) fibrils, but the Ab(1–40) fibrils display a significantly increased protection for the N-terminal residues Phe4–His14, suggesting that additional secondary structure is formed in this region. In contrast, the C-terminal residues Gly37–Val40 show a reduced protection that suggests a loss of secondary structure in this region and an altered filament assembly. The differences between the present study and other similar investigations suggest that subtle variations in fibril-preparation conditions may significantly affect the fibrillar architecture.
Place, publisher, year, edition, pages
2007. Vol. 404, no 1, 63-70 p.
IdentifiersURN: urn:nbn:se:umu:diva-13597PubMedID: 17280549OAI: oai:DiVA.org:umu-13597DiVA: diva2:153268