Rehovot, Israel: Scientists have discovered a previously unknown immune defence mechanism, revealing a potential goldmine for new antibiotics.
Researchers from Israel’s Weizmann Institute of Science found that the proteasome—a tiny structure present in every cell—has a hidden ability to produce bacteria-killing molecules, transforming our understanding of infection defence.
The proteasome is primarily known for breaking down old proteins for recycling.
However, findings published in Nature show that when a cell detects a bacterial infection, the proteasome changes structure and function, converting old proteins into antimicrobial agents that rip open bacterial membranes to kill them.

The research team, led by Prof. Yifat Merbl, referred to their discovery process as “dumpster diving,” as they analysed discarded protein fragments to identify natural antibiotics.
These newly identified antimicrobials were tested on bacteria in lab conditions and in mice with pneumonia and sepsis, yielding results comparable to some existing antibiotics.
Further experiments showed that disabling the proteasome in lab-grown cells made them significantly more susceptible to bacterial infections, such as Salmonella.

Images from the study captured Staphylococcus bacteria being destroyed as their outer layers were torn open by these naturally produced antimicrobials.
Prof. Daniel Davis, an immunologist at Imperial College London, described the findings as “extremely provocative and very interesting,” noting that they reveal an entirely new way our body fights infections.
While he emphasized the importance of this discovery, he also cautioned that developing these natural antibiotics into medical treatments will take time and further testing.
With antibiotic resistance responsible for over a million deaths annually, this breakthrough provides a promising new avenue to combat drug-resistant superbugs and improve global health.