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Journal of Nanomaterials
Volume 2016, Article ID 1863065, 10 pages
Research Article

Effects of End-Terminal Capping on Transthyretin (105–115) Amyloid Protofibrils Using Steered Molecular Dynamics

Department of Mechanical Engineering, Korea University, Seoul 136-701, Republic of Korea

Received 30 December 2015; Revised 31 March 2016; Accepted 10 April 2016

Academic Editor: Zhiping Xu

Copyright © 2016 Myeongsang Lee et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Numerous degenerative diseases are associated with amyloidosis, which can be caused by amyloid proteins. These amyloid proteins are generated from misfolded and denatured amyloid monomers under physiological conditions. Changes in protonation state, pH, ionic strength, and temperature, in addition to mutations, are related to the promotion of amyloidosis. Specifically, an understanding of the mechanical characteristics of amyloid protofibrils is important, since amyloid growth proceeds by a mechanism involving cycles of fragmentation and elongation. However, there remains a lack of knowledge of amyloid structural conformations and their mechanical characteristics, particularly considering end-terminal capping effects. In the present study, we investigated the mechanical characteristics of transthyretin amyloid protein (TTR), which have been implicated in cardiovascular disease, and specifically considered the contribution of end-terminal capping effects. Using steered molecular dynamics (SMD) simulations, we report different structural behaviors between uncapped and capped TTR amyloid protofibrils. We show that end-terminal capping strengthens the structural stability and improves the mechanical properties of amyloid protofibrils. This study provides useful information concerning the structural and mechanical characteristics of TTR amyloid protofibrils, with a particular emphasis on end-terminal capping effects.