The Evolution of Nature's First Motor: Unlocking the Secrets of Ancient Bacteria
A groundbreaking study led by the University of Auckland has shed new light on the evolutionary origins of one of nature's earliest motors, which emerged between 3.5 and 4 billion years ago to propel bacteria. This research, published in the journal mBio, offers a comprehensive understanding of the evolution of bacterial stators, proteins that function similarly to pistons in a car engine.
Dr. Caroline Puente-Lelievre, from the School of Biological Sciences, explains that stator proteins are embedded in the bacterial cell wall, converting charged particles (ions) into torque, enabling bacteria to swim. The scientists' investigation into stators involved analyzing genomic data from over 200 bacterial genomes, constructing evolutionary trees using advanced computational tools, modeling 3D protein structures, and conducting hands-on lab experiments.
The 3D shape of each protein is crucial to its function, and the researchers predicted the sequences and structures of ancestral proteins that existed millions or billions of years ago. They discovered that stators are typically composed of five identical versions of the protein MotA and two identical versions of the protein MotB, both derived from an ancient two-protein system that evolved to perform various functions.
Dr. Nick Matzke, a senior researcher from the University of Auckland, highlights the concept of 'co-opting simpler machines with simpler functions' in the evolution of complex machines. He draws a parallel between the development of protofeathers in dinosaur ancestors for warmth and their later redeployment for gliding or flying, suggesting that ancient bacteria may have repurposed ion flow tools for propulsion.
The study's key findings include the identification of torque-generating regions in stator proteins and the confirmation of their essential role in bacterial movement through functional assays. Despite billions of years of evolution, the fundamental features of these tiny engines remain remarkably unchanged and continue to be relevant today.
Assistant Professor Matthew Baker from UNSW Sydney emphasizes the significance of this research in the context of modern structural biology and microbiology. With the discovery of new sequences and tools like AlphaFold, scientists can instantly explore possible protein structures, contributing to a deeper understanding of the evolution of these ancient motors.
The research was funded by various organizations, including the Human Frontier Science Program, the University of Auckland Faculty of Science, the John Templeton Foundation, and the Alfred P. Sloan Foundation. The study's co-authors include Pietro Ridone, Dr. Jordan Douglas, Kaustubh Amritkar, and Assistant Professor Betül Kaçar.
This groundbreaking research not only enhances our understanding of the evolution of life's first motors but also opens up new avenues for exploration in the fields of structural biology and microbiology, inviting further investigation into the mysteries of ancient bacteria.
