Probing Charge Transport through Peptide Bonds

Joseph M. Brisendine, Sivan Refaely-Abramson, Zhen-Fei Liu, Jing Cui, Fay Ng, Jeffrey B. Neaton, Ronald L. Koder, Latha Venkataraman

Research output: Contribution to journalArticlepeer-review

Abstract

We measure the conductance of unmodified peptides at the single-molecule level using the scanning tunneling microscope-based break-junction method, utilizing the N-terminal amine group and the C-terminal carboxyl group as gold metal-binding linkers. Our conductance measurements of oligoglycine and oligoalanine backbones do not rely on peptide side-chain linkers. We compare our results with alkanes terminated asymmetrically with an amine group on one end and a carboxyl group on the other to show that peptide bonds decrease the conductance of an otherwise saturated carbon chain. Using a newly developed first-principles approach, we attribute the decrease in conductance to charge localization at the peptide bond, which reduces the energy of the frontier orbitals relative to the Fermi energy and the electronic coupling to the leads, lowering the tunneling probability. Crucially, this manifests as an increase in conductance decay of peptide backbones with increasing length when compared with alkanes.

Original languageEnglish
Pages (from-to)763-767
Number of pages5
JournalJournal of Physical Chemistry Letters
Volume9
Issue number4
DOIs
StatePublished - 15 Feb 2018
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Materials Science
  • Physical and Theoretical Chemistry

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