Scrapie-infected cells, isolated prions, and recombinant prion protein: A comparative study

Fourier -transform infrared microscopic spectra of scrapie-infected nervous tissue measured at high spatial resolution (~6(mu)m) were compared with those obtained from the purified, partly proteinase K digested scrapie isoform of the prion protein isolated from nervous tissue of hamsters infected with the same scrapie strain (263K) to elucidate similarities/dissimilarities between prion structure investigated in situ and ex vivo. A further comparison is drawn to the recombinant Syrian hamster prion protein SHaPrP90-232 after in vitro conformational transition from the predominantly (alpha)-helical isoform to (beta)-sheet-rich structures. It is shown that prion protein structure can be investigated within tissue and that detectability of regions with elevated (beta)-sheet content as observed in microspectra of prioninfected tissue strongly depends on spatial resolution of the experiment.