Norlin, Nils, Hellberg, Magnus, Filippov, Andrei, Sousa, Alioscka A., Gröbner, Gerhard, Leapman, Richard D., Almqvist, Nils and Antzutkin, Oleg N.. (2012) Aggregation and fibril morphology of the arctic mutation of Alzheimer’s Aβ peptide by CD, TEM, STEM and in situ AFM. Journal of Structural Biology, Vol.180 (No.1). pp. 174-189. ISSN 1047-8477

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Abstract

Morphology of aggregation intermediates, polymorphism of amyloid fibrils and aggregation kinetics of the "Arctic" mutant of the Alzheimer's amyloid beta-peptide, A beta((1-40))(E22G), in a physiologically relevant Tris buffer (pH 7.4) were thoroughly explored in comparison with the human wild type Alzheimer's amyloid peptide, wt-A beta((1-40)), using both in situ atomic force and electron microscopy, circular dichroism and thioflavin T fluorescence assays. For arc-A beta((1-40)) at the end of the 'lag'-period of fibrillization an abrupt appearance of similar to 3 nm size 'spherical aggregates' with a homogeneous morphology, was identified. Then, the aggregation proceeds with a rapid growth of amyloid fibrils with a variety of morphologies, while the spherical aggregates eventually disappeared during in situ measurements. Arc-A beta((1-40)) was also shown to form fibrils at much lower concentrations than wt-A beta((1-40)): <= 2.5 mu M and 12.5 mu M, respectively. Moreover, at the same concentration, 50 mu M, the aggregation process proceeds more rapidly for arc-A beta((1-40)): the first amyloid fibrils were observed after Ca. 72 h from the onset of incubation as compared to approximately 7 days for wt-A beta((1-40)). Amyloid fibrils of arc-A beta((1-40)) exhibit a large variety of polymorphs, at least five, both coiled and non-coiled distinct fibril structures were recognized by AFM, while at least four types of arc-A beta((1-40)) fibrils were identified by TEM and STEM and their mass-per-length statistics were collected suggesting supramolecular structures with two, four and six beta-sheet laminae. Our results suggest a pathway of fibrillogenesis for full-length Alzheimer's peptides with small and structurally ordered transient spherical aggregates as on-pathway immediate precursors of amyloid fibrils. (C) 2012 Elsevier Inc. All rights reserved

Item Type:	Journal Article
Divisions:	Faculty of Science > Physics
Journal or Publication Title:	Journal of Structural Biology
Publisher:	Academic Press
ISSN:	1047-8477
Date:	2012
Volume:	Vol.180
Number:	No.1
Page Range:	pp. 174-189
Identification Number:	10.1016/j.jsb.2012.06.010
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Restricted or Subscription Access
URI:	http://wrap.warwick.ac.uk/id/eprint/52140

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