A key role for lysine residues in amyloid ?-protein folding, assembly, and toxicity.

ABSTRACT: A combination of hydrophobic and electrostatic interactions is important in initiating the aberrant self-assembly process that leads to formation of toxic oligomers and aggregates by multiple disease-related proteins, including amyloid ?-protein (A?), whose self-assembly is believed to initiate brain pathogenesis in Alzheimer's disease. Lys residues play key roles in this process and participate in both types of interaction. They also are the target of our recently reported molecular tweezer inhibitors. To obtain further insight into the role of the two Lys residues in A? assembly and toxicity, here we substituted each by Ala in both A?40 and A?42 and studied the impact of the substitution on A? oligomerization, aggregation, and toxicity. Our data show that each substitution has a major impact on A? assembly and toxicity, with significant differences depending on peptide length (40 versus 42 amino acids) and the position of the substitution. In particular, Lys16?Ala substitution dramatically reduces A? toxicity. The data support the use of compounds targeting Lys residues specifically as inhibitors of A? toxicity and suggest that exploring the role of Lys residues in other disease-related amyloidogenic proteins may help understanding the mechanisms of aggregation and toxicity of these proteins.

SUBMITTER: Sinha S 

PROVIDER: S-EPMC3382451 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature