Science: New technology solves mystery of Tetrahymena respiration

Tetrahymena, a tiny, single-celled organism, has been found to hide a surprising secret: It respires—using oxygen to generate cellular energy—unlike other organisms, such as plants, animals or yeast

"We thought that by studying other organisms, we would Learned about breathing, but it shows how much we still don't know

Tetrahymena are free-living, single-celled organisms that are usually found swimming quietly around ponds by flapping their hairs or cilia

"It's a huge part of the biosphere, but we don't think about them too much," Maldonado said

Tetrahymena, like all other eukaryotes and some bacteria, consume oxygen to generate energy through respiration, said James Letts, assistant professor of molecular and cellular biology in the UC Davis School of Biological Sciences

Oxygen enters at the end of a series of chemical reactions during respiration

New Approaches to Structural Biology

There are some clues that Tetrahymena's electron transport chain is somewhat different, Letts said

Maldonado, Letts and co-first author Long Zhou used new methods from structural biology to reveal the electron transport chain in Tetrahymena

Cryo-electron microscopy freezes samples to extremely low temperatures, producing images at almost atomic resolution

In this way, they were able to scan thousands of protein images and identify the structures of 277 proteins in three large assemblies representing Tetrahymena's electron transport chain at near atomic resolution

By revealing gaps in our knowledge of a fairly common creature, the work shows our blind spot in biodiversity, Letts said

Part of this work was performed using cryo-electron microscopy at the Biological Electron Microscopy Core Facility in the UC Davis School of Biological Sciences

article title

Structures of Tetrahymena's respiratory chain reveal the diversity of eukaryotic core metabolism