The amphibian antimicrobial peptide uperin 3.5 is a cross-α/cross-β chameleon functional amyloid.
© Kristian Bell/Moment/Getty Images
An antimicrobial peptide found on the skin of an Australian toadlet alters shape in the presence of bacteria to help ward off infections.
The discovery of how the peptide, named uperin 3.5, undergoes this shape change could inform the development of new antibiotic drugs.
A team that included members of the Spanish National Research Council solved the three-dimensional molecular structure of uperin 3.5. This peptide is secreted by Mjoberg’s toadlet, a diminutive relative of toads that grows up to 2.5 centimetres in length and that lives in north-western Australia.
The researchers found when the peptide encounters a bacterial membrane, it changes from a helical form into tight, twisted fibrils. In so doing, it becomes toxic to intruding microbes. It may be possible to use similar strategies when developing artificial antimicrobial drugs.
- PNAS 118, e2014442118 (2021). doi: 10.1073/pnas.2014442118