Proteins Conduct Electricity
A remarkable finding at the single-molecule level shows a protein can conduct a large amount of electricity.
A press release from the University of Cardiff describes how researchers isolated a single protein molecule and measured the passage of a current when placed between electrodes. This could represent a fundamental property of proteins that might explain their function. Two collaborators at the university said, “The highly conducting nature of this protein was a surprise and the result raises questions about the fundamental nature of electron transfer in proteins.” Could it be that proteins operate as transistors?
The team showed that the protein could carry large currents, equivalent to a human hair carrying one amp. The team also discovered that current flow could be regulated in much the same way as transistors, the tiny devices driving computers and smartphones, work but on a smaller scale: the proteins are only a quarter of the size of current silicon based transistors.
The finding represents a leap forward in measurement at the nano scale. “Prior to this work, measurement of millions, if not billions of proteins was only possible, so losing crucial details of how an individual molecule functions.” The team used scanning tunneling microscopy (STM) to read the electronics of a single molecule of cytochrome b562, a protein just 5 nanometers (billions of a meter) long.
While the focus of the press release was on human engineering of this conductance for nanotechnology, the discovery may elucidate how the cell’s protein machines work. PhysOrg‘s headline was, “Electronics of nature’s nano machines.” Its summary reads, “A team from the Cardiff University’s Schools of Biosciences and Physics and Astronomy have made a breakthrough in our understanding of proteins – the workhorse molecules of the cell and nature’s very own nano machines.”
While it’s premature to compare proteins to human electrical tools, it is known that electron or proton transfer is essential to some of them, such as photosynthesis, ATP synthase and other machines in the respiratory chain. What about the motor proteins dynein, kinesin, and myosin? What about the flagellar motor, mitochondrial machines and DNA transcription and translation machines? How is ATP energy transduced into proteins’ mechanical actions? This is a discovery to watch. If your own cells can be someday described as electronic machines, wouldn’t that be cool?