A giant 8 million dalton machine in methane making microbes forms one continuous electron loop.

Tiny microbes called methanogens make most of the world's methane, a strong greenhouse gas. Scientists mapped the detailed shape of a huge molecular machine these microbes use to make energy. The machine has 252 protein chains and more than 600 tiny parts that move electrons. It forms two ring shaped sections joined by a middle piece. Together they make one big loop that moves electrons in a circle. This loop connects the last step and the first step of methane production. The machine can also swap one part for a different one. This lets the microbe adjust to different surroundings. This exact design only shows up in one major group of methanogens, not in others.

Integrity screen: passed (3 checks) Checked 22 July 2026. Retraction record: none. DOI resolves at doi.org. Metadata record found (Nature). Read the source

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