Long-range donor-acceptor electron transport mediated by alpha-helices

TL;DR

This paper investigates how electrons can be transported efficiently over long distances along alpha-helical polypeptides via polaron formation, demonstrating high efficiency and stability at physiological temperatures.

Contribution

It introduces a model showing that specific couplings enable efficient long-range electron transfer mediated by polarons in alpha-helices, with stability under thermal fluctuations.

Findings

Achieves up to 90% electron transfer efficiency.

Demonstrates stability of transfer at physiological temperatures.

Identifies coupling schemes that optimize transport.

Abstract

We study the long-range electron and energy transfer mediated by a polaron on an $\alpha$-helix polypeptide chain coupled to donor and acceptor molecules at opposite ends of the chain. We show that for specific parameters of the system, an electron initially located on the donor can tunnel onto the $\alpha$-helix, forming a polaron which then travels to the other extremity of the polypeptide chain where it is captured by the acceptor. We consider three families of couplings between the donor, acceptor and the chain, and show that one of them can lead to a 90\% efficiency of the electron transport from donor to acceptor. We also show that this process remains stable at physiological temperatures in the presence of thermal fluctuations in the system.