Molecular dynamical study on ion channeling through peptide nanotube

We theoretically study the possibility of ion channeling through peptide nanotubes (PNTs). After designing the minimal peptide nanorings (PNRs) and their aggregated form (peptide nanotubes, PNT) computationally, we carry out molecular dynamics (MD) calculations for cation channeling. The present MD calculations show that cation channeling through PNTs occurs. Furthermore, inter-ring hydrogen bonds (HBs) survive and maintain the tubular form of PNTs during cation channeling. We introduce mobility such that cation channeling can be evaluated quantitatively. As the ionic radius of the cation becomes smaller, the effective relaxation time τ becomes larger. Accordingly, mobilities of 10 ^-2∼10 ^-3[cm ²/volt/sec] are calculated. In contrast, when an anion (F ^-) passes through the PNT, the inter-ring HBs are broken, thus inducing breakdown of the peptide backbone. Consequently, H atoms from the broken HBs surround the channeling anion (F ^-) and halt its motion.