Multistage conformational transition in peptide nanotube induced by temperature and/or external electric field

The effect of temperature and external electric field on the structure of a base class of peptide nanotubes (PNT), composed of cyclo-[(Gly)4] peptide nanoring (G4PNR) subunits, is studied using the density functional theory (DFT) and molecular dynamics (MD). Several asymmetric PNT conformations are identified, which are likely to occur at finite temperature, in addition to the stable optimal (temperature T = 0) conformers identified in previous studies. Temperature and electrical field-induced transitions between conformers are investigated at multiple temperatures/ field strengths. Notably, it is shown that these may enable atomistic control of PNT length, torque, pore radius, dipole moment, and linearity. Combined with the tunable nature of the PNT base properties (including the functional binding groups), this suggests that PNTs have the potential to become a much more important tool in bio-nanotechnology and medicine.