UF College of medicine office of research
The Nemudryi Lab’s research on bacterial Schlafen proteins was highlighted in a May 21 Science news feature that graced the cover.
By Manny Rea
Investigators in the Department of Biochemistry and Molecular Biology have collectively garnered more than 151,000 article accesses in 2026 from recent studies published in journals including Nature Metabolism, Nature Microbiology, and Nature Communications. Among these studies, work by Drs. Artem Nemudryi and Anna Nemudraia was highlighted in a May 21 Science news feature. The article described the lab’s discovery that Schlafen proteins act as an ancient bacterial defense against viruses and may illuminate the evolutionary origins of related antiviral proteins in humans.
Led by Artem Nemudryi, Ph.D., principal investigator and assistant professor, and Anna Nemudraia, Ph.D., research assistant professor, the lab studies prokaryotic immunity against bacteriophages, how bacteria defend against viruses, and cellular RNA repair mechanisms, how cells fix broken RNA.
The team also investigates Schlafen proteins. Derived from the German word for “sleep,” Schlafen proteins pause a cell’s development; by putting a cell to “sleep,” protein synthesis halts, starving any invading virus of the resources it needs to replicate efficiently. Human cells use this strategy to inhibit modern viruses like HIV-1 and Zika.
The manuscript, “Bacterial Schlafen Proteins Mediate Phage Defence,” was published March 9 in Nature Microbiology. The lab’s first-ever study, it was later discussed in the broader Science feature story, “Brothers in Arms,” about how human immune defenses emerged during bacteria’s struggles for survival against viruses billions of years ago.
While researchers already knew that mammalian and human Schlafen proteins act as antiviral factors by using a “scissor” nuclease to cut tRNA and prevent protein synthesis, their bacterial counterparts remained a mystery. Nemudryi and Nemudraia’s team reverse-engineered this immunity connection by proving that bacterial Schlafen proteins use a closely related antiviral mechanism.
A massive computational search identified 5,930 unique Schlafen sequences across prokaryotes including bacteria. The breakdown revealed that 97.1% of these proteins act like two-part security systems: they pair the same tRNA-cutting nuclease with 55 sensors to detect unique viral threats — a modular design akin to the human process.
Additionally, the team focused on a specific system, RorSlfn5, which is a Schlafen protein sequence from the bacteria Raoultella ornithinolytica, to uncover exactly how this ancient defense works. They discovered the system uses a specialized immunoglobulin-like sensor to detect a specific viral trigger: the “tail assembly chaperone” that a virus needs to build its body. Once triggered, the rest of the established process continues. The lab also found that the system uses a very similar biochemical reaction, another shared characteristic that supports the idea that human Schlafen immunity evolved from ancient microbial defense systems.
“This evolutionary link blows my mind,” Nemudryi said. “Billions of years separate us from bacteria, but our bodies still use these ancient proteins to fight viruses.”
The Science Magazine story highlighted their discovery and others as an emerging body of work confronting the previous notion that human immunity evolved independently.
Nemudraia said, “There is a famous saying in biology: ‘What is true for E. coli is true for the elephant.’ It is exciting to be part of a field that continues to uncover these connections, and we are grateful to the people in our lab behind this discovery.”
You can read the Lab’s paper at https://www.nature.com/articles/s41564-026-02277-8 and the full Science Magazine story at https://www.science.org/content/article/ancient-wars-between-microbes-gave-us-key-immune-defenses.