By David Coppedge

Single molecule of electron transfer protein cytochrome b562 bound between two gold electrode surfaces.

A remarkable finding at the single-molecule level shows a protein can conduct a large amount of electricity.

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….

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