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Updated: Jul 7, 2026
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Electrochemical Detection of Deuterium Kinetic Isotope Effect on Extracellular Electron Transport in Shewanella oneidensis MR-1
Published on: April 16, 2018
Intermolecular biological electron transfer: an electrochemical approach
Katsumi Niki1, James R Sprinkle, Emanuel Margoliash
1Beckman Institute, California Institute of Technology, Pasadena, CA 91125, USA. kniki@bilrc.caltech.edu
Bioelectrochemistry (Amsterdam, Netherlands)
|January 12, 2002
Summary
Electron transfer rates between gold electrodes and immobilized cytochrome c depend on alkanethiol chain length. Short chains limit electron transfer due to a protein rearrangement, suggesting lysine-13 is crucial for efficient electron transfer.
Area of Science:
- Electrochemistry
- Biophysics
- Surface Science
Background:
- Cytochrome c is a key protein in cellular respiration and electron transfer.
- Self-assembled monolayers (SAMs) are widely used to functionalize electrode surfaces.
- Understanding electron transfer at bio-electrode interfaces is crucial for biosensor development.
Purpose of the Study:
- To investigate electron transfer (ET) rates between a gold electrode and immobilized cytochrome c.
- To determine the influence of alkanethiol chain length on ET rates.
- To elucidate the mechanism of rate limitation in short-chain alkanethiols.
Main Methods:
- Potential modulated electroreflectance spectroscopy was used to measure ET rates.
- Cytochrome c was immobilized on gold electrodes via alkanethiol SAMs with varying chain lengths.
- A mutant cytochrome c (RC9-K13A) was used to probe the role of lysine-13.
Main Results:
- Electron transfer rates showed a linear dependence on chain length for long alkanethiols.
- Electron transfer rates became independent of chain length for short alkanethiols.
- A mutant cytochrome c with lysine-13 replaced by alanine exhibited ET rates over six orders of magnitude lower than native cytochrome c.
Conclusions:
- Electron transfer through short alkyl chains is limited by a protein conformational rearrangement preceding the ET event.
- This rearrangement, termed "gating," involves cytochrome c shifting to a configuration that facilitates efficient ET pathways.
- Lysine-13 of cytochrome c is proposed to be critical for facilitating efficient electron transfer to the carboxylate terminus.
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