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Fully Atomistic A beta 40 and A beta 42 Oligomers in Water: Observation of Porelike Conformations
Journal article   Peer reviewed

Fully Atomistic A beta 40 and A beta 42 Oligomers in Water: Observation of Porelike Conformations

Matthew J. Voelker, Bogdan Barz and Brigita Urbanc
Journal of chemical theory and computation, v 13(9), pp 4567-4583
01 Sep 2017
PMID: 28727426

Abstract

Chemistry Chemistry, Physical Physical Sciences Physics Physics, Atomic, Molecular & Chemical Science & Technology
Oligomers formed by amyloid beta-protein (A beta) are central to Alzheimer's disease (AD) pathology, yet their structure remains elusive. Of the two predominant A beta alloforms, A beta 40 and A beta 42, the latter is more strongly associated with AD. Here, we structurally characterized A beta 40 and A beta 42 monomers through pentamers which were converted from previously derived coarse-grained (DMD4B-HYDRA) simulations into all-atom conformations and subjected to explicit-solvent MD. Free energy landscapes revealed that structural differences between A beta 40 and A beta 42 conformations increase With oligomer order up to trimers. All conformations display high statistical coil and turn content (40-50%) with minor beta-strand and a-he lical content (<10%). A beta 40 tetramers and pentamers exhibit significantly more elongated morphologies than the respective A,542 conformations. Unlike the initial DMD4B-HYDRA conformations, fully atomistic A beta 40 and A beta 42 trimers, tetramers, and pentamers form water-permeable pores, whereby the tendency for pore formation sharply increased with oligomer order and is the highest for A,642 pentamers. Previous studies reported that A beta oligomers form ion channels when embedded into a cellular membrane, which causes an abnormal ion flux and eventually leads to cell death. Our findings reveal an extraordinary ability of A beta oligomers to form pores in pure water prior to their insertion into a membrane and thus provide support to the ion channel hypothesis of AD.

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Collaboration types
Domestic collaboration
International collaboration
Web of Science research areas
Chemistry, Physical
Physics, Atomic, Molecular & Chemical
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