Found everywhere from the human mouth to the surface of the skin, microorganisms known as Archaea — meaning "ancient things" — were only distinguished from bacteria as recently as the late 1970s.
Scientists have since identified these tiny, single-celled organisms as a major processor of methane, a greenhouse gas around 30 times more powerful than carbon dioxide at trapping heat.
Distinct species of Archaea are said to play an outsized role in regulating Earth's climate by processing over 80% of the methane produced in the world's oceans.
But despite their importance, Archaea remain notoriously difficult to isolate, grow, and study.
Now, researchers in the lab of Nikhil Malvankar at Yale's Microbial Sciences Institute have uncovered a key feature of how these ancient microbes work: through hair-like protein structures distinct from the electrical nanowires previously discovered in bacteria.
Using a nearly pure strain of Archaea developed by collaborators in the Netherlands, the team employed electron microscopy to reveal the atomic structure of this nanowire machinery. The structures help the microbes transfer electrons as they break down and recycle methane compounds in oxygen-deprived environments, such as those deep beneath the ocean floor.
Published in Nature Communications , the findings provide the first molecular-level understanding of how methane-consuming Archaea use nanowires to transfer electrons, shedding new light on their role in the global methane cycle and potentially opening new avenues for methane conversion technologies.
Cong Shen and Martijn Wissink, respectively of Yale and Radboud University, Netherlands, were co-first authors of the study. Malvankar is an associate professor of Molecular Biophysics and Biochemistry at Yale School of Medicine. Co-senior author Cornelia Welte is a professor of microbiology at Radboud University.
