Geobacter constructs "nanowires" as a result of an electric field applied to electricity-producing biofilms. These nanowires are composed of cytochrome OmcZ and have a 1000 times higher conductivity and three times stronger stiffness than the nanowires of cytochrome OmcS important in natural environments, allowing bacteria to transport electrons more than 100 times their size.
A bacteria-made ultra-stable protein nanowire offers clues on how to deal with climate change.
Global warming is causing significant and immediate damage to life on Earth. Methane is 30 times more powerful than CO2 at trapping heat. Microbes reproduce half of this methane, leading to a greater quantity of greenhouse gases than plants can absorb. This decreases the Earth's ability to act as a carbon sink and contributes to rising global temperatures.
A Yale University team led by Yangqi Gu and Nikhil Malvankar, who operate in the Microbial Sciences Institute, has discovered surprising wire-like properties of a protein that accounts for up to 80% of methane emissions from ocean sediments that protect the Earth.
This protein nanowire had previously demonstrated that it has the highest conductivity known to date, enabling bacteria to generate the greatest electrical power. However, no one has discovered how bacteria make them and why they have such an extreme conductivity.
Yangqi and the team were able to see the nanowire's atomic structure and discover that hemes are packed tightly to carry electrons very rapidly with ultra-high stability. It also explains how these bacteria can survive without oxygen-like membrane-ingestible molecules and form communities that can carry electrons up to 100 times the size of their organism.
Malvankar explained that we are using these heme wires to generate electricity and to combat climate change by understanding how methane-eating microbes utilize similar heme wires.
Yangqi Gu, Matthew J. Guberman-Pfeffer, Vishok Srikanth, Fabian Giska, Kallol Gupta, Fadel A. Samatey, and Nikhil S. Malvankar, 2 February 2023, Nature Microbiology. DOI: 10.1038/s41564-022-01315-5
Matthew Guberman-Pfeffer, Vishok Srikanth, Cong Shen, Fadel Samatey and colleagues Prof. Victor Batista, Prof. Kallol Gupta, and Fabian Giska are among the authors of Malvankar Lab findings.