Aggregation of soluble, monomeric beta- amyloid (Abeta) to oligomeric and then insoluble fibrillar Abeta is a key pathogenic feature in development of Alzheimer's disease (AD). Increasing evidence suggests that toxicity is linked to diffusible Abeta oligomers, rather than to insoluble fibrils. The use of naturally occurring small molecules for inhibition of Abeta aggregation has recently attracted significant interest for development of effective therapeutic strategies against the disease. A natural polyphenolic flavone, Kaempferol-3-O-rhamnoside (K-3-rh), was utilized to investigate its effects on aggregation and cytotoxic effects of Abeta42 peptide. Several biochemical techniques were used to determine the conformational changes and cytotoxic effect of the peptide in the presence and absence of K-3-rh.

Proteins and peptides expressed in the prokaryotic system often form inclusion bodies. Solubilization and refolding procedures can be used for their recovery, but this process remains difficult. One strategy for improving the solubility of a protein of interest is to fuse it to a highly soluble protein. To select a suitable fusion partner capable of solubilizing the aggregation-prone (inclusion body–forming) proteins and peptides, Escherichia coli thermostable proteins were identified and tested. Among them, trigger factor (TF) protein was selected because of its high expression and stability. Using an expression system based on fusion to TF, selected proteins and peptides that otherwise form inclusion bodies were expressed in soluble state and were purified like other soluble proteins. This system provides a convenient method for production of aggregation-prone proteins and peptides. Suppression of Inclusion by Fusion Bacterial expression systems are often used for the synthesis and purification of recombinant proteins. Although this technique has been successfully used for numerous proteins, it may not be efficient for other proteins due to complications such as poor expression, low yield, instability, and difficulty in purification. Expression of certain proteins in Escherichia coli can often result in the accumulation of insoluble aggregates, forming inclusion bodies. Therefore, it is important to design expression strategies, such as using fusion proteins, to improve the production of soluble proteins. Prompted by a recent description that some thermostable proteins improve the stability and purification of target proteins fused to them, Thapa and colleagues in the lab of II-Seon Park at Chosun University (Gwanju, Republic of Korea) have done a systematic screen for E. coli thermostable proteins capable of enhancing the solubility of target proteins fused to them. To isolate therm...