Cao, C. et al. Nat. Commun. 10, 4918 (2019).

Nanopores are useful tools for sensing, especially in regard to long-read DNA sequencing, as well as into proteomic applications and beyond. As such, a great deal of research has gone into identifying artificial and biological nanopores to optimize and expand their applicability. One well-characterized nanopore is aerolysin, a β-pore-forming toxin from Aeromonas hydrophila. To expand the versatility of aerolysin, Cao et al. first sought to understand the structure–function relationship of this pore. They used a range of computational and biophysical techniques to reveal that the ion selectivity and sensing are conferred by a combination of the narrow diameter of the protein’s ‘cap’ and electrostatics. The researchers also identified mutants with improved molecular detection of nucleic acids and peptides. Their results highlight the utility of aerolysin and the benefits of mutational strategies for improving nanopore-based sensing.