Monitoring site-specific conformational changes in real-time reveals a misfolding mechanism of the prion protein.

ABSTRACT: During pathological aggregation, proteins undergo remarkable conformational re-arrangements to anomalously assemble into a heterogeneous collection of misfolded multimers, ranging from soluble oligomers to insoluble amyloid fibrils. Inspired by fluorescence resonance energy transfer (FRET) measurements of protein folding, an experimental strategy to study site-specific misfolding kinetics during aggregation, by effectively suppressing contributions from inter-molecular FRET, is described. Specifically, the kinetics of conformational changes across different secondary and tertiary structural segments of the mouse prion protein (moPrP) were monitored independently, after the monomeric units transformed into large oligomers OL, which subsequently disaggregated reversibly into small oligomers OS at pH 4. The sequence segments spanning helices ?2 and ?3 underwent a compaction during the formation of OL and elongation into ?-sheets during the formation of OS. The ?1-?1-?2 and ?2-?3 subdomains were separated, and the helix ?1 was unfolded to varying extents in both OL and OS.

SUBMITTER: Sengupta I 

PROVIDER: S-EPMC6590988 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature