Effect of oscillation dynamics on long-range electron transfer in a helical peptide monolayer

Abstract

Electron transfer (ET) reactions via helical peptides composed of –(Aib-Pro)_n– were studied in self-assembled monolayers and compared with –(Ala-Aib)_n– peptides. Short Aib-Pro peptides showed slightly higher ET rates due to the better electronic coupling of the Pro residue. But, the 24mer Aib-Pro peptide showed a smaller ET rate than the corresponding Ala-Aib peptide. On the basis of DFT calculations, the deceleration of the ET rate of the longer Aib-Pro peptide is considered to be due to the smaller number of active modes of accordion-like oscillations than the Ala-Aib peptide, which has a strong influence on a long-range ET reaction.