Evidence for protein misfolding in the presence of nanoplastics

摘要

The possible effect of plastic nanoparticles of waste origin on biological systems is still unclear and could pose a severe threat. Model studies at the molecular level are urgently needed in order to help reveal the interplay between these particles and biological systems, and thereby to indicate the direction of further research. In the present study, simulated annealing molecular dynamics is adjusted and applied to generate an array of conformations for a sample peptide oligoalanine possibly binding to polyethylene and nylon 6,6 nanoplastics. The resulting structures, with a diameter of up to 5 nm, were investigated with the aid of static quantum chemical calculations. The obtained data unequivocally show that both plastic nanoparticles influence the relative stability of alpha-helix,beta-hairpin, and other conformations strongly. Polyethylene nanoparticle increases the stability of the helical foldamer. Nylon 6,6 nanoplastic offers strong plastic-peptide interactions on its surface, making the unfolding of the peptide thermodynamically highly favorable. These results further underscore that nanoplastics can do significant molecular-level damage to living organisms via facilitating the misfolding and denaturation of proteins. Furthermore, it is apparent that plastics can have very different effects on living matter depending upon their composition, and hence experiments with any single kind of plastics (eg, polystyrene) should not be considered generally valid for all nanoplastics.