Researchers at the Karolinska Institutet have shown how sperm proteins attack the oval barrier. The study reveals how the sperm recognizes the surface of the oval and penetrate it, previously unclear. All this has been documented with 3D images of the fertilization process. This will help to better understand the reproduction mechanics in mammals.
Luca Jovine's team used data from the European Synchrotron Radiation Facility (ESRF), obtained by X-ray crystallography. The researchers thus showed the interaction between sperm and ZP2 proteins. The molecule contains repeated sequences that play a key role in recognizing gametes. Among other things, it is very similar to a protein with similar functions, VERL, which is present in molluscs.
Taking advantage of the similarity between ZP2 and VERL, the researchers used the aliotids as models. They are very simple molluscs, which facilitated the observation of VERL protein at work. Scholars have thus studied how the protein binds to lysine, a protein present in sperm. The process opens a hole in the oval barrier, allowing the sperm to enter.