Structural destabilization of chignolin under the influence of oscillating electric fields

The structural response of chignolin to 1 V/nm electric fields of different frequencies has been studied with molecular dynamics simulations and stochastic modeling. It was found that oscillating electric fields induce conformational changes to chignolin that are frequency dependent. For frequencies comparable with or smaller from the orientational self-diffusion rate, the peptide destabilizes after performing an oscillatory motion between the two possible directions of the electric field axis. For higher frequencies the field effects are averaged out and chignolin performs a Brownian rotation diffusion maintaining its native conformation. Stochastic modeling can describe chignolin's oscillatory motion equally well with the molecular dynamics simulations. The time needed for these changes to take place has a stochastic nature depending, beyond frequency, on factors related with the hydrogen bonds' stability and their geometrical arrangement in the structure. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3699389]