Abstract
Amyloid β 42 (Aβ42) is an inherently disordered peptide, whose toxic actions are believed to play important roles in the etiology of Alzheimer's disease. Four fibril structures of the peptide that display broadly similar characteristics were recently published, but a systematic comparison of these structures is lacking. In this paper, a topological framework was created to enable such understanding and produced new insights into subtle structural elements that underlie the overall structural diversity. A DFT-based analysis illuminated some of the energetic differences that arise as a consequence.