An AlphaFold model of Tmem81, a membrane protein involved in the fusion of egg and sperm.Credit: Google DeepMind/EMBL-EBI (CC-BY-4.0)For nearly a decade, Andrea Pauli, a biochemist at the Research Institute of Molecular Pathology in Vienna, has been trying to work out how sperm and egg get together.In 2018, her laboratory found a protein on the surface of zebrafish (Danio rerio) eggs, called Bouncer, that was essential for fertilization. But Pauli’s team and others struggled to show how Bouncer ...