High-yield Production of Amyloid-ß Peptide Enabled by a Customized Spider Silk Domain.

During storage in the silk gland, the N-terminal domain (NT) of spider silk proteins (spidroins) keeps the aggregation-prone repetitive region in solution at extreme concentrations. We observe that NTs from different spidroins have co-evolved with their respective repeat region, and now use an NT that is distantly related to previously used NTs, for efficient recombinant production of the amyloid-ß peptide (Aß) implicated in Alzheimer's disease. A designed variant of NT from Nephila clavipes flagelliform spidroin, which in nature allows production and storage of ß-hairpin repeat segments, gives exceptionally high yields of different human Aß variants as a solubility tag. This tool enables efficient production of target peptides also in minimal medium and gives up to 10 times more isotope-labeled monomeric Aß peptides per liter bacterial culture than previously reported.

Structural studies of amyloid-ß peptides: Unlocking the mechanism of aggregation and the associated toxicity.

Alzheimer's disease (AD) is one of the most prevalent neurodegenerative diseases worldwide. Formation of amyloid plaques consisting of amyloid-ß peptides (Aß) is one of the hallmarks of AD. Several lines of evidence have shown a correlation between the Aß aggregation and the disease development. Extensive research has been conducted with the aim to reveal the structures of the neurotoxic Aß aggregates. However, the exact structure of pathological aggregates and mechanism of the disease still remains elusive due to complexity of the occurring processes and instability of various disease-relevant Aß species. In this article we review up-to-date structural knowledge about amyloid-ß peptides, focusing on data acquired using solution and solid state NMR techniques. Furthermore, we discuss implications from these structural studies on the mechanisms of aggregation and neurotoxicity.