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Amide Neighbouring‐Group Effects in Peptides: Phenylalanine as Relay Amino Acid in Long‐Distance Electron Transfer |
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| Authors: | Joses G. Nathanael Dr. Luke F. Gamon Dr. Meike Cordes Prof. Paul R. Rablen Prof. Thomas Bally Prof. Katharina M. Fromm Prof. Bernd Giese Prof. Uta Wille |
| Affiliation: | 1. School of Chemistry, Bio21 Institute, The University of Melbourne, Parkville, Victoria, Australia;2. Department of Chemistry, University of Basel, Basel, Switzerland;3. Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, PA, USA;4. Department of Chemistry, University of Fribourg, Fribourg, Switzerland |
| Abstract: | In nature, proteins serve as media for long‐distance electron transfer (ET) to carry out redox reactions in distant compartments. This ET occurs either by a single‐step superexchange or through a multi‐step charge hopping process, which uses side chains of amino acids as stepping stones. In this study we demonstrate that Phe can act as a relay amino acid for long‐distance electron hole transfer through peptides. The considerably increased susceptibility of the aromatic ring to oxidation is caused by the lone pairs of neighbouring amide carbonyl groups, which stabilise the Phe radical cation. This neighbouring‐amide‐group effect helps improve understanding of the mechanism of extracellular electron transfer through conductive protein filaments (pili) of anaerobic bacteria during mineral respiration. |
| Keywords: | density functional calculations electron transfer kinetics neighboring-group effects peptides radical cations |