Sentence: Utilization of this topological feature revealed the switch sites ( where the beginning of exposure of previously hidden `` hot spots '' of fibril-forming happens , in consequence a further opportunity for protein aggregation is provided ; 188-202 ) of the conformational conversion of the normal a-helix-rich prion protein PrP C to the b-sheet-rich PrP Sc that is thought to be responsible for a group of fatal neurodegenerative diseases , transmissible spongiform encephalopathies. 
 Section: finding