1. Academic Validation
  2. Residues 17-20 and 30-35 of beta-amyloid play critical roles in aggregation

Residues 17-20 and 30-35 of beta-amyloid play critical roles in aggregation

  • J Neurosci Res. 2004 Jan 15;75(2):162-171. doi: 10.1002/jnr.10859.
Ruitian Liu 1 Chad McAllister 2 Yuri Lyubchenko 2 Michael R Sierks 1
Affiliations

Affiliations

  • 1 Department of Chemical and Materials Engineering, Arizona State University, Tempe, Arizona.
  • 2 Department of Microbiology, Arizona State University, Tempe, Arizona.
Abstract

We examined the effects of co-incubating nine different Abeta Peptide Fragments with full-length Abeta1-40 (Abeta40) on protein aggregation. Six fragments enhanced aggregation of Abeta40 (Abeta1-28, 12-28, 17-28, 10-20, 25-35 and 17-40), while three Others did not (Abeta1-11, 1-16, and 20-29). All of the Peptides that enhanced aggregation contained either residues 17-20 or 30-35, indicating the importance of these regions for promoting aggregation of full-length Abeta. Abeta25-35 in particular increased both the rate and extent of aggregation of Abeta40 considerably as indicated by fluorescence staining. Atomic force microscope imaging (AFM) indicates the increase in fluorescence staining with Abeta25-35 is primarily due to increased formation of oligomers and protofibrils rather than formation of large amyloid fibrils. AFM images of Abeta25-35 when incubated alone also indicate formation of aggregates and long thin filaments. The increase in formation of the small toxic oligomeric morphology of Abeta40, along with formation of Abeta25-35 oligomers and thin filaments, represent two different potential pathways for Abeta25-35 toxicity. The critical roles of residues 17-20 and 30-35 of Abeta provide further insight into mechanism that underlie the formation of toxic aggregates in Alzheimer Disease (AD) and suggest targets for the design of beta-sheet breakers to modulate the aggregation and inhibit toxicity of full-length Abeta.

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