Backbone-Constrained Peptides: Temperature and Secondary Structure Affect Solid-State Electron Transport

Cunlan Guo, Jingxian Yu, John R. Horsley, Mordechai Sheves, David Cahen, Andrew D. Abell

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The primary sequence and secondary structure of a peptide are crucial to charge migration, not only in solution (electron transfer, ET), but also in the solid-state (electron transport, ETp). Hence, understanding the charge migration mechanisms is fundamental to the development of biomolecular devices and sensors. We report studies on four Aib-containing helical peptide analogues: Two acyclic linear peptides with one and two electron-rich alkene-based side chains, respectively, and two peptides that are further rigidified into a macrocycle by a side bridge constraint, containing one or no alkene. ETp was investigated across Au/peptide/Au junctions, between 80 and 340 K in combination with the molecular dynamic (MD) simulations. The results reveal that the helical structure of the peptide and electron-rich side chain both facilitate the ETp. As temperature increases, the loss of helical structure, change of monolayer tilt angle, and increase of thermally activated fluctuations affect the conductance of peptides. Specifically, room temperature conductance across the peptide monolayers correlates well with previously observed ET rate constants, where an interplay between backbone rigidity and electron-rich side chains was revealed. Our findings provide new means to manipulate electronic transport across solid-state peptide junctions.

Original languageEnglish
Pages (from-to)10951-10958
Number of pages8
JournalJournal of Physical Chemistry B
Volume123
Issue number51
DOIs
StatePublished - 26 Dec 2019
Externally publishedYes

Bibliographical note

Publisher Copyright:
Copyright © 2019 American Chemical Society.

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