Tuning the structure of monomeric amyloid beta peptide by the curvature of carbon nanotubes

Carbon nanotubes can affect the self-assembly of amyloid beta peptides (A beta) related to neurodegenerative diseases. We use molecular dynamics (MD) to investigate the effects of carbon nanotubes (CNT) on the conformational evolution of monomeric A beta(1-42) peptide. The chirality of CNT varies from (10, 10), (15, 15), (20, 20) and (25, 25) that corresponds to declining curvatures. We show that the adhesion of peptide on CNT surface leads to internal structures predisposes to collapse, which might be reasonable methods to impede the initial nucleation and self-assembly. Adsorption induce the loss of the peptides' native structures. Adsorption and subsequent denaturation accompanies by a loss of surface hydration of peptide. When the curvature of CNT decreases, peptide spread almost completely over the CNT surface. Conversely, peptide will wrap around the CNT when the curvature of CNT is high. Peptide adsorption onto CNT also reduces their alpha-helical content and beta-sheet ratio, indicating that the CNT significantly affect the formation of alpha-helical structures while inducing random coil conformations. The arrangement of peptides on CNT surface relates to the affinity of various amino acids onto CNT. These insights provide useful information for understanding the binding and winding tendency of peptides on carbon nano-structures' surface. (C) 2019 Elsevier Ltd. All rights reserved.