Researchers from the University of Auckland (New Zealand) have traced the evolution of one of nature’s most ancient mechanisms – the microscopic motor that allows bacteria to move. According to the project leader, biologist Carolina Puente-Lelievre, scientists were able to create the most complete model of origin to datestator proteins– structures that work like pistons, converting the flow of ions into rotational motion. The results were published in the journalmBio.

Stator proteins are built into the cell wall of bacteria and provide the rotation of the flagellum, a thin “tail” that pushes the cell forward like a microscopic propeller.These proteins convert the energy of the ion flow into torque, causing the flagellum to rotate at speeds of up to hundreds of revolutions per second.

Scientists used the AlphaFold artificial intelligence algorithm (for which they were awarded the Nobel Prize in 2024) torestoration of the three-dimensional structure of ancient proteinsand analysis200 bacterial genomes. Comparison of data made it possible to construct an evolutionary “tree” and trace the path of the emergence of the first protein “motors” on the planet.

How evolution invented the engine

It turned out that stator proteins originated from simpleion carriers– molecules that pumped charged particles through the membrane. Over time, this system became complex, turning into a full-fledged motor.

Just as feathers in ancient dinosaurs first served for ther gulation and later for flight, the flow of ions in early bacteria became the basis for the mechanism of movement.

Modern stator complexes are composed of proteinsMotAAndMotBforming a channel for the passage of ions and generation of torque. To confirm the function of these proteins, the researchers deleted a key region of the gene in bacteriaE. coli– and the cells completely lost their ability to swim.

“We literally turned off the engine and the bacteria stopped moving,” explains Puente-Lelievre.

The first motors on Earth

Bacteria are some of the planet’s oldest inhabitants, dating back than 3.5 billion years ago when the oceans were green with minerals and the skies orange with volcanic gases. It was then that nature “invented” the first biological engine, which remains effective today.

“Despite billions of years of evolution, the operating principles of these microscopic motors have remained virtually unchanged,” says Matthew Baker from the University of New South Wales.