Swiss scientists said Wednesday they had made a major breakthrough in research into causes of mad cow disease by discovering the three-dimensional shape of prions, a protein found in nerves and the brain.
The chemical structure of prions, one of more than 100,000 different proteins in the human body, has been known for some time but the physical form remained a mystery until now.Scientists at Zurich's Federal Institute of Technology (ETH) said mapping prions would allow researchers to hunt for changes in the structure of the proteins that may cause the disease, bovine spongiform encephalopathy (BSE), and a related brain-wasting disease in humans.
"Discovering the structure provides a new basis for biological and medical research into prions and prion diseases," biophysics professor Kurt Wuethrich told a news conference.
Wuethrich and molecular biology professor Rudolf Glockshuber, who headed the research at ETH, said their findings would appear in a letter to the science journal Nature due for publication Wednesday.
The two researchers said their work was based on a widespread hypothesis that a mutated type of prion causes BSE in cows, its human form Creutzfeldt-Jakob disease, and related diseases.
The ETH researchers were able to map the twisting shape of prions by using nuclear magnetic resonance, a technology that pinpoints the position of separate compunds making up the prion and therefore allows a composite picture to be drawn.
The prions mapped were normal ones taken from mice and are believed to be nearly identical to human prions. Abnormal prions were not examined because of technical barriers.
However, Wuethrich and Glockshuber said having an accurate map of a normal prion would allow researchers to replace or alter each of its segments to discover whether a change produces disease.
"Further research could then possibly show what kind of medicines would have to affect what part of a prion in order to treat the disease," Wuethrich said.
"Maybe this could lead to designing molecules to replace prion defects," Glockshuber added.
Both scientists said it was too early to say whether their findings would lead to a breakthough in treatment of degenerative brain diseases.