Species-specific recognition between the egg extracellular matrix (zona pellucida) and sperm is the first step of mammalian fertilization. This paper reports the 2.3 Å resolution structure of the 'zona pellucida filament' of the egg, which act as sperm receptors. The structure supports the presence of ZP–N repeats within the amino-terminal region of ZP2 and other vertebrate zona pellucida/vitelline proteins, and has implications for egg coat architecture and the post-fertilization block to polyspermy and speciation.
- Magnus Monné
- Ling Han
- Luca Jovine
