Through the holes: the biotechnological potential of actinoporins (and other PFPs).

Pore-forming proteins (PFPs) are singular polypeptides used by all kinds of organisms for attack or defence. They defy the stereotypical classification between water-soluble and membrane proteins. Within this large family of proteins, bacterial hemolysins and sea anemone actinoporins stand out as candidates for transforming these toxins into therapeutic or biotechnological devices. Over the past two decades, many examples have been published where these toxic proteins have been adapted to perform single-molecule tasks such as biosensing, sequencing of proteins and nucleic acids, discriminating protein chemical modifications, proteomics analyses, or even the use of DNA in computational approaches. Lately, PFPs have also been incorporated as templates for designing new artificial nanoreactors to catalyse different chemical reactions. A promising alternative within this idea is the recent publication of a proof of concept showing that actinoporins can be converted into biosustainable plastic-degrading nanoreactors. It is also discussed how optimisation and development of future PFP-based nanoreactors with improved activity and new specificities seem to be a venue worth to explore in order to degrade the contaminating waste material made of plastics from very different chemical compositions.