Unravelling the structural changes in α-helical peptides on interaction with convex, concave, and planar surfaces of boron-nitride-based nanomaterials

Abstract

The interaction between polyalanine (PA) peptide in a α-helical conformation with boron-nitride-based nanomaterials such as boron nitride nanotube (BNNT) and boron nitride sheet (BNS) has been studied using classical molecular dynamics simulations and density functional theory (DFT)-based calculations. PA interacts with convex (exohedral mode) and concave (endohedral mode) surfaces of BNNT. The interaction of PA with the planar surface of BNS is also investigated. It is evident from the findings that the helical structure of the peptide undergoes conformational changes, which depend on the nature of curvature of the surface. It is found from the results that transition of α-helical conformation to turns takes place in the presence of these BNS, in contrast with the interaction of PA with graphene. The large structural changes in the PA upon interaction with BNS compared with graphene are due to the appreciable van der Waals interaction between PA and BNS. The DFT calculations have also predicted that the dispersion interaction is responsible for the stabilization of alanine on the surface of boron nitride sheet. Furthermore, to assess the effect of amino acid composition of peptide in the interaction pattern with BNS, we have also explored the adsorption of polyphenylalanine (PF), amphiphilic peptide (Nano-1), and a peptide derived from membrane protein (SNARE) on the surface of BNS. Results reveal that BNS induces the secondary structural changes in these peptides.