Electric field controlled uphill electron migration along α-helical oligopeptides

A systematic study on applied electric field effects (E-app) on electron transfer along the peptides is very important for the regulation of electron transfer behaviors so as to realize the functions of proteins. In this work, we computationally investigated the uphill migration behaviors of excess electrons along the peptide chains under E-app using the density functional theory method. We examined the electronic property changes of the model alpha-helical oligopeptides, the dynamics behavior of an excess electron along the peptide chains under E-app opposite to the internal dipole field of peptides. We found that E-app of different intensities can effectively modulate the electron-binding abilities, Frontier molecular orbital (FMO) energies and distributions, dipole moments and other corresponding properties with different degrees. The electron-binding abilities of alpha-helical oligopeptides revealed by vertical electron affinity and FMO energies decrease in weak E-app and then increase greatly in high E-app, while the dipole moments change mildly in weak E-app and increase significantly until a threshold and then become gentle in high E-app. Analysis of FMO and electron distributions indicates that an excess electron can migrate uphill from the N-terminus to the C-terminus of the alpha-helical peptides in an irregular jump mode as E-app linearly increases. Another interesting finding is that alpha-helical peptides with diverse chain lengths have different sensitivities to E-app. The longer the peptide is, the more obvious the effects of E-app are. Additionally, compared to the E-app effect on linear oligopeptides, we summarized the systematic rule about the E-app effect on excess electron migration uphill along the peptide chains. Clearly, this work not only enriches the information of the E-app effect on electronic properties and electron transfers in the helical peptides, but also provides a new perspective for modulating electron migration behaviors in protein electronics engineering.

Automated summary

This study systematically investigates the effects of applied electric fields on electron transfer along peptide chains, revealing that different intensities of the electric field can modulate electron-binding abilities, molecular orbital energies, and dipole moments of alpha-helical oligopeptides. Additionally, it demonstrates that longer peptides exhibit more significant effects of the electric field, and provides new insights for modulating electron migration behaviors in protein electronics engineering.