Generation of Infectious Prions Amenable to Site-specific Click Chemistry

Prion diseases are a group of fatal neurodegenerative diseases that proceed through the templated conversion of the normal PrP ^C protein to a self-propagating and infectious form, termed PrP ^Sc . This conversion process is central to disease progression. However, due to difficulties in producing functional PrP ^Sc molecules that can be selectively modified with chemical probes, many aspects of PrP ^Sc biology cannot be directly studied. To overcome this limitation, we substituted p-azido-L-phenylalanine (AzF), a small click chemistry-reactive amino acid, for tryptophan residue 99 of PrP ^C . W99AzF PrP ^C substrate can efficiently and faithfully propagate either infectious or non-infectious PrP ^Sc conformers in vitro . Critically, W99AzF PrP ^Sc amyloid fibrils remain amenable to click chemistry by various ligands after the prion conversion process. Through the combination of site-specific substitution, the modularity of click chemistry, and the functional diversity of click labels, a multitude of modified prions can now be produced to ask targeted questions about the biochemical and biological basis of prion infectivity.