Dimerization of the Aβ42 under the Influence of the Gold Nanoparticle: A REMD Study.

Advances in Alzheimer's disease (AD) are related to the oligomerization of Amyloid β (Aβ) peptides. Therefore, alteration of the process can prevent AD. We investigated the Aβ₄₂ dimerization under the effects of gold nanoparticles using temperature replica-exchange molecular dynamics (REMD) simulations. The structural change of dimers in the presence and absence of the gold nanoparticle, Au₅₅, was monitored over stable intervals. Physical insights into the oligomerization of Aβ were thus clarified. The computed metrics indicate that Au₅₅ affects the progress of oligomerization. Specifically, the presence of the gold nanoparticle significantly modifies the structure of dimeric Aβ₄₂. The β-content experienced a substantial decrease with the induction of Au₅₅. The turn and coil-contents are also decreased under the effects of the gold nanoparticle. However, the α-content of the dimer exhibited a rigid increase. The influence of gold nanoparticles on the dimeric Aβ₄₂ differs significantly from that of silver nanoparticles, which reduce β-content but increase coil-, turn-, and α-contents. The nature of inhibition will be discussed, in which the vdW interaction plays a driving force for the interaction between the Aβ₄₂ dimer and the gold nanoparticle.