Submitted to: Journal of Molecular Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/13/2000
Publication Date: N/A
Interpretive Summary: The prion diseases include economically important disorders of sheep, cattle, deer and elk. The prion disease in cattle is thought to be transmissible to humans. The diseases are invariably fatal. The cause of this novel group of diseases is believed to be an abnormally folded version of a normal mammalian protein. Contact with the abnormal form of the protein causes the normal protein to be converted to the pathogenic, transmissible molecule. The molecular mechanisms by which the normal protein binds the abnormal protein and converts to the abnormal form are not well understood. In this study, a group of specialized antibodies were used as molecular probes to examine different parts of the normal protein. The study demonstrated that different regions of the normal protein interact, demonstrating that these regions are close together in the normally folded state. These studies demonstrate important biochemical features of the normal protein and will contribute to additional studies of pathogenesis and treatment of prion disorders.
Technical Abstract: In this study, we have characterized the epitopes of a panel of twelve monoclonal antibodies (Mabs) directed to normal human cellular prion protein (PrPC) using ELISA and Western blotting of recombinant PrP or synthetic peptide fragments of PrP. The antibodies of the first group, which is represented by Mabs 5B2 and 8B4 react with PrP23-145, indicating that the epitopes for these Mabs are located in the 23-145 N-terminal region of human PrP. The second group includes Mabs 1A1, 6H3, 7A9, 8C6, 8H4, 9H7 and 2G8. These antibodies bind to epitopes localized within N- terminally truncated recombinant PrP90-231. Finally, Mabs 5C3, 2C9 and 7A12 recognize both PrP23-145 and PrP90-231, suggesting that the epitopes for th group are located in the region encompassing residues 90-145. By Western blotting with PepSpotTM, only three of Mabs studied (5B2, 8B4 and 2G8) bind to linear epitopes that are present in thirteen-residue long synthetic peptides corresponding to human PrP fragments. The remaining nine Mabs appear to recognize conformational epitopes. Two N-terminus- specific Mabs were found to prevent the binding of the C-terminus- specific Mab 6H3. This observation suggests that the unstructured N- terminal region may influence the local conformation within the folded C- terminal domain of prion protein.