FTIR study on thermal denaturation and aggregation of ~(90-232) recombinant hamster prion protein SHaPrP

摘要

We have investigated the temperature induced denaturation and aggregation of the recombinant fragment SHaPrP~(90-232) of the hamster prion protein by Fourier transform infrared (FTIR) spectroscopy in H_2O and D_2O buffers.Difference spectra of this denaturation/aggregation reaction revealed a decrease of a-helical and turn structures and an increase of intermolecularly formed antiparallel beta-sheet structure.Compared to previously examined critical oligomers in H_2O buffer,the temperature induced aggregates of SHaPrP~(90-232) exhibited a less rigid but still strong hydrogen bonding pattern as indicated by the beta-sheet specific difference band at 1624 cm~(-1).The denaturation/aggregation temperature of SHaPrP~(90-232) was consistently determined using the beta-sheet specific difference band observed in the H_2O or in the D_2O experiments.Further,the spectra obtained for the critical oligomers produced in appropriate buffer systems at 25degC and at 37 degC revealed no significant differences in secondary structure.