Scientists have determined the three dimensional structure of the egg protein that helps the sperm stick during fertilisation.
The structure could not only help determine why infertility occurs, but also lead to a completely new type of contraceptive.
Luca Jovine of the Karolinska Institute in Stockholm, Sweden, and colleagues studied the chicken version of the protein using X-ray and then fitted the mammalian version of the sperm receptor protein onto that structure with the help of a computer programme.
As well as providing clues to how sperm defects block fertilisation, the findings could lead to a new type of contraceptive, reports New Scientist.
Working out the shape of the surface involved in sperm binding raises the possibility of designing small molecules to disrupt the process, and so prevent conception, which might have fewer side effects than hormone-based drugs.
The researchers now hope to look at the structure of egg-sperm complexes to see how the two sides of the process work together.