Chemists have built peptides that can be switched on and off with light, and the switch holds for weeks. The work, by McCann, Prischich and colleagues, was published in Chemical Science on 2 November 2026.
It is early laboratory chemistry, a long way from any use in people.
What a stapled peptide is
Stapled peptides are short chains of amino acids locked into a helix by a chemical brace. Holding the helix in shape can help a peptide bind its target protein more tightly.
A brace that responds to light
The team used a new light-sensitive brace, called azobispyrazole, on two well-studied peptides taken from the proteins Bak and p53.
Shining light flips the brace. In the experiments this made the peptides more helical and helped them bind more tightly to their targets, Bcl-xL for the Bak peptide and MDM2 for the p53 peptide. A second burst of light reverses the change.
A switch that holds
Once the brace was flipped, it had a half-life of 65 days at 21 °C, and about half a year in the Bak peptide.
That means the peptide does not slip back on its own, so its shape can be controlled with light rather than by waiting for it to relax.
How early this is
The results come from chemistry in the laboratory. Whether such peptides work in cells or animals, and how light could be delivered in practice, are questions for later studies.