Incorporation of an Azobenzene β-Turn Peptidomimetic into Amyloid-β to Probe Potential Structural Motifs Leading to β-Sheet Self-Assembly

  • Todd M. Doran
  • Bradley L. Nilsson
Part of the Methods in Molecular Biology book series (MIMB, volume 1777)


Alzheimer’s disease (AD) is characterized by chronic neurodegeneration and the insidious accumulation of senile plaques comprised of the amyloid-β (Aβ) peptide. An important goal in AD research is to characterize the structural basis for how Aβ aggregates exert their noxious effects on neurons. We describe herein synthetic steps to incorporate a light-controlled β-turn mimetic, 3-(3-aminomethylphenylazo)-phenylacetic acid (AMPP), into the backbone of a putative turn region within Aβ. AMPP adopts a rigid β-hairpin turn when azobenzene is in the cis conformation, and can adopt an extended “β-arc” turn in the trans-azobenzene conformation. The long lifetimes of these conformationally stable isomers permit detailed biochemical analyses that help to clarify the controversial role played by these two types of turns during the toxic misfolding pathway of Aβ. Methods to photo-nucleate the cis- or trans-AMPP isomeric turns in aqueous buffer are also described. Finally, we detail selected techniques to characterize the Aβ aggregates derived from these photoisomerized variants.

Key words

Azobenzene Photoswitch Photoisomerization Amyloid-β Alzheimer’s disease β-Hairpin β-Arc 



This work was made possible by a grant from the Alzheimer’s Association (NIRG-08-90797). We thank Professor Joseph P. Dinnocenzo for helpful discussions regarding photoisomerization methods and Karen Bentley of the University of Rochester Medical Center Electron Microscopy Core for assistance with transmission electron microscopy.


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© Springer Science+Business Media, LLC, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Medicinal Chemistry, Institute for Translational NeuroscienceUniversity of MinnesotaMinneapolisUSA
  2. 2.Department of ChemistryUniversity of RochesterRochesterUSA

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