What is it about?
The simple act of breathing is among the most familiar ways we convert nutrients to energy – inhaling molecules of oxygen and harmlessly breathing out unwanted material. But when our usual disposal mechanisms fail, the accumulated electrons can produce the kind of toxic event that causes many diseases, including cancer. Studying life processes like an electronic circuit, scientists at Yale have devised a novel way to identify the underlying mechanism that relieves oxidative stress as part of so-called biochemical reduction-oxidation (or "redox") reactions. Published in PNAS, the researchers found a new escape route that acts to defuse these ticking time bombs -- a wire made up of chains of amino acids that are present in a third of all proteins
Photo by Alex Dukhanov on Unsplash
Why is it important?
We know these ring-shaped amino acid chains contribute to making proteins more robust. But we also found that the same chains can behave as electron wires. Overcoming challenges that have hampered past protein conductivity studies, the team used a 4-electrode technique to measure electron flow in individual protein crystals. Although electrons had previously been observed "tunneling" through proteins, the team discovered electrons "hopping" over distances greater than a thousand times further than previously observed. We are answering a long-standing question of how electrons travel far through a protein.
Read the Original
This page is a summary of: Intrinsic electronic conductivity of individual atomically resolved amyloid crystals reveals micrometer-long hole hopping via tyrosines, Proceedings of the National Academy of Sciences, December 2020, Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.2014139118.
You can read the full text:
Electronic control of bacterial behavior via natural and synthetic protein nanowires Deep in the ocean or underground, where there is no oxygen, Geobacter “breathe” by projecting tiny protein filaments called “nanowires” into the soil, to dispose of excess electrons resulting from the conversion of nutrients to energy. These nanowires enable the bacteria to perform environmentally important functions such as cleaning up radioactive sites and generating electricity. Using cryo-electron microscopy, our lab has discovered that heme molecules line up to create a continuous path along which electrons travel with surrounding proteins acting as an insulation for these wires (Cell 2019 & Nature Chemical Biology 2020) This discovery of nanowires was selected as Proteopedia’s highest impact structures of the century and the New York Times commented as “a strong reminder of how ready we are to ignore things we cannot imagine.” Our work explains how bacteria use nanowires for interspecies electron transfer (Science 2010), and electricity production via biofilm communities (Nature Nano 2011). Our work thus provides new insights into bacterial survival mechanisms to control their pathophysiology and ecology and demonstrates a bottom-up approach to develop self-repairing and robust electronic materials. Following are three major research themes of our lab: 1) Assembly machinery: We are identifying the nanowire assembly machinery using genetic tools combined with x-ray crystallography and cryo-electron microscopy and tomography. 2) Conductivity Mechanism: Existing models of biological electron transfer cannot fully explain such high conductivity in proteins. We are building a new fundamental framework by performing conductivity measurements as a function of several physical and chemical probes. 3) Synthetic Protein Nanowires: We are crystallizing conductive proteins and incorporating non-standard amino acids to develop self-assembling electronically and optical biomaterials.
The following have contributed to this page