SCIENCE • EVIDENCE • DISCOVERY
Watching an Enzyme Build Penicillin’s Core
Time-resolved X-ray snapshots reveal fleeting steps in antibiotic biosynthesis.
ADDED OCTOBER 28, 2026
What the enzyme does
Isopenicillin N synthase (IPNS) uses iron and oxygen to convert a three-amino-acid starting molecule into the fused rings characteristic of penicillins. One is the four-membered beta-lactam ring.
How researchers made the movie
Enzyme microcrystals traveled on a moving tape into oxygen, which started the reaction. Ultrafast X-ray pulses sampled crystals after different reaction times. Combining many structural snapshots reconstructed the sequence; this was not an ordinary camera filming a single molecule.
What they discovered
The study resolved unexpected intermediates, including a thioaldehyde temporarily detached from the iron center and a structure containing the beta-lactam ring before the second ring formed. Water molecules and protein movements helped control the chemistry.
Why it matters—and what comes next
Knowing how enzymes manage reactive intermediates could guide catalyst engineering and antibiotic research. The study explains a biosynthetic mechanism; it does not itself establish a new antibiotic, a human treatment, or a solution to antibiotic resistance.
Sources and further reading
- University of Oxford research summary — October 9, 2026
- Rabe and colleagues, Nature Catalysis: time-resolved IPNS study (2026)