© CNRS Images/media 2001
Mad cow disease, like other neurodegenerative diseases, is probably due to the presence of an abnormal form of the prion, a protein found in mammalian nerve cells. A collaborative project by a team of biochemists from the Laboratoire d'enzymologie et biochimie structurale in Gif-sur-Yvette and a team of physicists from the ESRF (European Synchrotron Radiation Facility) in Grenoble has led to an understanding of the three-dimensional structure of the yeast prion.The prion crystals are positioned in the path of a beam of x-rays produced in the Grenoble synchrotron. The x-rays strike the crystals, and rays diffracted in different directions form spots on a detector. Based on the position and relative intensity of the spots, the three-dimensional structure of the prion protein can be reconstructed and modeled by computer. The researchers have observed the existence of a flexible zone inside the molecule which may be the source of the appearance and transmission of the abnormal prion.