DOI: 10.1101/499061Dec 20, 2018Paper

Theory of concentric β-barrel structures: models of amyloid beta 42 oligomers, annular protofibrils, and transmembrane channels

BioRxiv : the Preprint Server for Biology
H Robert GuyRakez Kayed

Abstract

Amyloid beta (Abeta) peptides are a major contributor to Alzheimers disease. Previously, our group proposed molecular models of Abeta42 hexamers with two concentric antiparallel beta-barrels that act as seeds from which dodecamers, octadecamers, both smooth and beaded annular protofibrils, and transmembrane channels form. Since then, numerous aspects of our models have been supported by experimental findings. Here we develop a more extensive range of models to be consistent with dimensions of assemblies observed in electron microscopy images of annular protofibrils and transmembrane assemblies. These models have the following features: Dodecamers with 2-concentric beta-barrels are the major components of beaded annular protofibrils (bAPFs). These beads merge to form smooth annular protofibrils (sAPFs) that have three or four concentric beta-barrels. Channels form from two to nine hexamers. Antiparallel C-terminus S3 segments form an outer transmembrane beta-barrel. Half of the monomers of vertically asymmetric 12mer to 36mer channels form parallel transmembrane S2 beta-barrels, and S1-S2 (N-terminus and middle) segments of the other half of the monomers form aqueous domains on the cis side of the membrane. Unit cells of 42-54me...Continue Reading

Related Concepts

Alzheimer's Disease
Integral Membrane Proteins
Ion Channel
Electron Microscopy
Amyloid beta-Peptides
Amyloid beta-protein (1-42)
Structure of Outer Nuclear Layer of Retina
Membrane
Monomer
Beta Barrel

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