Machinery behind bacterial nanowires discovered

Almost all living things breathe oxygen to eliminate the excess electrons produced when nutrients are converted into energy. However, most microbes that mitigate pollution and climate change don’t have access to oxygen. Instead, these bacteria—buried underground or living deep under the oceans—have developed a way to eliminate electrons by “breathing minerals” from the soil through tiny protein filaments called nanowires.

In previous research, a team led by Nikhil Malvankar, Associate Professor of Molecular Biophysics and Biochemistry at Yale’s Microbial Sciences Institute, showed that nanowires are made up of a chain of heme molecules, just like hemoglobin in our blood, thrust into the environment to move electrons. To leverage the power of these microbes, however, scientists need to know how those nanowires are assembled.

The Yale team led by Cong Shen has now discovered the machinery that assembles the nanowires, making practical applications possible. Of the 111 heme proteins, only three are known to polymerize to become nanowires.

The research is published in the journal Cell Chemical Biology.

Not only did the team identify the surrounding machinery that makes it possible for these proteins to become nanowires, but they also demonstrated that changing some of the machinery’s components can accelerate nanowire reproduction and bacterial growth. This is an important next step in engineering bacteria to efficiently produce electricity, clean pollutants from water, and lower atmospheric methane levels.