How Viruses May Help Us Defeat Antibiotic Resistance

Leon Wirz
6 hours ago
5 min read

Nature February 2026 | California Institute of Technology & Texas A&M University

Introduction

Antibiotic resistance is one of the most pressing challenges in modern medicine. According to global estimates, antimicrobial resistance (AMR) already contributes to millions of deaths each year and could become one of the leading causes of mortality by 2050 if new therapies are not developed.

One major difficulty in antibiotic development is that many existing drugs target the same bacterial processes, allowing pathogens to evolve resistance relatively quickly. As a result, scientists are increasingly searching for new biological targets within bacterial cells that could be exploited for future antibiotics.

One particularly promising but underexplored target is a protein called MurJ, which plays a critical role in bacterial cell wall synthesis. Without a functional cell wall, bacteria cannot survive.

A new study published in Nature investigates how certain viruses that infect bacteria (known as bacteriophages) have evolved proteins that specifically block MurJ. By revealing the molecular mechanism behind this process, the research opens the door to designing a new class of antibiotics inspired by viral proteins.

The Core Discovery

The researchers discovered that several unrelated bacteriophages have independently evolved small proteins that disable the MurJ transporter, a key enzyme required for bacterial cell wall construction.

MurJ functions as a lipid II flippase. Its job is to transport lipid II, a crucial building block of bacterial peptidoglycan, from the inside of the cell membrane to the outside, where the cell wall is assembled. If this transport step is blocked, the bacterium can no longer synthesize its protective cell wall.

The study found that three distinct viral proteins (called SglM, SglPP7, and SglCJ3) all inhibit MurJ by locking the protein into a specific conformation that prevents lipid II transport.

Remarkably, these viral proteins share almost no sequence similarity. Yet they evolved to target the same bacterial protein using a similar structural strategy. This phenomenon is known as convergent evolution, where different biological systems independently arrive at the same solution to a problem.

The findings suggest that MurJ represents a particularly vulnerable “weak point” in bacterial physiology.

How the Study Was Conducted

To understand how the viral proteins inhibit MurJ, the researchers combined structural biology, microbiology, and biochemical experiments.

First, they produced complexes of the MurJ transporter bound to viral lysis proteins in E. coli. These complexes were then analyzed using cryo-electron microscopy (cryo-EM), a high-resolution imaging method capable of resolving atomic-level structures of proteins embedded in membranes.

Using cryo-EM, the team determined the three-dimensional structures of MurJ bound to three different viral inhibitors:

SglM (from RNA phage M)
SglPP7 (from Pseudomonas phage PP7)
SglCJ3 (from a predicted phage called Changjiang3)

The resulting structures reached resolutions of about 3.6–3.7 Å, allowing researchers to visualize the precise interactions between MurJ and the viral peptides.

In addition to structural work, the team performed:

Mutational analyses to identify critical residues for inhibition
Cell lysis assays to measure bacterial killing
peptidoglycan synthesis experiments to confirm that MurJ inhibition blocks cell wall production

Together, these experiments revealed both the structural mechanism and functional consequences of MurJ inhibition.

Key Findings

The study produced several important insights.

1. Viral proteins lock MurJ in an inactive state

All three viral peptides bind to the same region of MurJ and trap the transporter in an outward-facing conformation that prevents lipid II transport. Because MurJ must cycle between inward- and outward-facing states to move lipid II across the membrane, this lock effectively halts the entire cell wall synthesis process.

2. The inhibition site is structurally conserved

Despite their different sequences, the viral proteins bind to a shared interface formed by transmembrane helices 2 and 7 of MurJ.

These helices undergo major structural rearrangements during the lipid II transport cycle. Blocking this region therefore stops the protein’s functional motion.

3. Key electrostatic interactions stabilize inhibition

The viral peptides contain negatively charged residues that interact with positively charged amino acids inside MurJ’s central cavity.

Important MurJ residues include:

Lys46
Arg53
Arg270
Lys368

These residues are also essential for MurJ’s normal function, making them particularly attractive targets for drug design.

4. The binding pocket is accessible to drugs

The MurJ cavity targeted by the viral proteins faces the periplasmic side of the bacterial membrane, meaning that potential drugs would not need to cross the entire membrane barrier.

This feature makes MurJ a more practical drug target than many intracellular bacterial enzymes.

Limitations of the Study

Despite its importance, the study also has several limitations.

First, the work was performed primarily in bacterial laboratory systems, particularly Escherichia coli. It remains unclear how easily MurJ inhibitors could be translated into clinically useful antibiotics against a broad range of pathogens.

Second, the viral inhibitors studied here are peptides embedded in membranes, which are difficult to convert directly into small-molecule drugs.

Another limitation is that in vitro assays for MurJ transport activity are still underdeveloped, making it harder to screen potential inhibitors efficiently.

Finally, bacteria may still evolve resistance mutations in MurJ, although the strong evolutionary conservation of the target site could limit this possibility.

Relevance for Switzerland

Antimicrobial resistance represents a growing challenge for healthcare systems worldwide, including Switzerland.

Swiss hospitals already face increasing rates of resistant pathogens such as:

MRSA (methicillin-resistant Staphylococcus aureus)
ESBL-producing Enterobacteriaceae
carbapenem-resistant Gram-negative bacteria

New antibiotic classes targeting MurJ could significantly improve treatment options for such infections.

Switzerland is also home to major pharmaceutical companies and multiple biotech startups that are actively investing in antimicrobial research. Structural insights such as those provided in this study are precisely the type of knowledge required for structure-based drug design, a common strategy in modern pharmaceutical development.

If MurJ inhibitors can be translated into drugs, they could eventually reduce hospital stays, intensive care costs, and complications related to resistant infections, all of which place a growing burden on healthcare systems and insurers.

Potential Impacts of a Successful Therapy

If researchers succeed in translating these findings into antibiotics, several major impacts could follow.

A new MurJ-targeting drug class could:

Treat infections resistant to existing antibiotics
Provide combination therapies to slow resistance evolution
Reduce mortality from multidrug-resistant bacterial infections
Expand the antibiotic pipeline, which has stagnated in recent decades

Because MurJ is highly conserved across many bacterial species, inhibitors could potentially have broad-spectrum activity, although this still needs to be tested experimentally.

Risks

Despite its promise, MurJ-targeted therapy also carries potential risks.

Bacteria could still develop resistance through:

mutations in the MurJ binding interface
compensatory mechanisms for lipid II transport
reduced drug uptake or increased efflux

Additionally, antibiotics targeting fundamental cellular processes may disrupt beneficial microbiota, a common challenge in antimicrobial therapy.

Finally, structural insights alone do not guarantee drug development success. Translating structural biology into clinically approved drugs remains a complex and costly process that often takes more than a decade.

Overall Assessment

This study provides one of the clearest demonstrations to date of how viral proteins can reveal new antibiotic targets.

By solving high-resolution structures of MurJ bound to three different viral inhibitors, the researchers uncovered a previously underexploited vulnerability in bacterial cell wall synthesis.

The fact that multiple viruses independently evolved proteins that attack the same transporter strongly suggests that MurJ represents a critical evolutionary weak point in bacteria.

While significant work remains before this discovery can be translated into clinical therapies, the study provides a detailed molecular blueprint that could guide the development of a completely new antibiotic class.

What Comes Next

Several key steps will likely follow this work.

Researchers will now aim to:

design small-molecule inhibitors that mimic viral peptides
develop high-throughput MurJ activity assays
test MurJ inhibitors in pathogenic bacteria
explore additional viral lysis proteins that may target similar pathways

Interestingly, the authors also note that many bacteriophage lysis genes remain unexplored, meaning that viruses may contain a vast library of potential antibacterial mechanisms waiting to be discovered.

In an era where antibiotic resistance threatens global health, such viral strategies could become an important source of future therapies.

Reference

Li, Y.E., Antillon, S.F., Baron, G.F. et al.

Convergent MurJ flippase inhibition by phage lysis proteins. Nature (2026). https://doi.org/10.1038/s41586-026-10163-w