Effect of graphene oxide on the conformational transitions of amyloid beta peptide: A molecular dynamics simulation study.

Abstract

The interactions between nanomaterials (NMs) and amyloid proteins are central to the nanotechnology-based diagnostics and therapy in neurodegenerative disorders such as Alzheimer's and Parkinson's. Graphene oxide (GO) and its derivatives have shown to modulate the aggregation pattern of disease causing amyloid beta (Aβ) peptide. However, the mechanism is still not well understood. Using molecular dynamics simulations, the effect of graphene oxide (GO) and reduced graphene oxide (rGO) having carbon:oxygen ratio of 4:1 and 10:1, respectively, on the conformational transitions (alpha-helix to beta-sheet) and the dynamics of the peptide was investigated. GO and rGO decreased the beta-strand propensity of amino acid residues in Aβ. The peptide displayed different modes of adsorption on GO and rGO. The adsorption on GO was dominated by electrostatic interactions, whereas on rGO, both van der Waals and electrostatic interactions contributed in the adsorption of the peptide. Our study revealed that the slight increase in the hydrophobic patches on rGO made it more effective inhibitor of conformational transitions in the peptide. Alpha helix-beta sheet transition in Aβ peptide could be one of the plausible mechanism by which graphene oxide may inhibit amyloid fibrillation.

• Authors: Lokesh Baweja, Kanagasabai Balamurugan, Venkatesan Subramanian, Alok Dhawan
• Journal: Journal of molecular graphics & modelling (J Mol Graph Model) Vol. 61 Pg. 175-85 (Sep 2015) ISSN: 1873-4243 [Electronic] United States
• PMID: 26275931 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2015 Elsevier Inc. All rights reserved.

Chemical References

• Amyloid beta-Peptides
• Oxides
• Peptide Fragments
• amyloid beta-protein (1-40)
• Graphite

Topics

• Adsorption
• Amino Acid Sequence
• Amyloid beta-Peptides (antagonists & inhibitors, chemistry)
• Binding Sites
• Graphite (chemistry)
• Humans
• Hydrophobic and Hydrophilic Interactions
• Molecular Dynamics Simulation
• Molecular Sequence Data
• Oxidation-Reduction
• Oxides (chemistry)
• Peptide Fragments (antagonists & inhibitors, chemistry)
• Protein Binding
• Protein Structure, Secondary
• Protein Structure, Tertiary
• Static Electricity
• Structural Homology, Protein
• Surface Properties
• Thermodynamics