Poster abstracts
Poster number 19 submitted by Christian ONeil
Determination of protofilament composition in amyloid fibrils by scanning transmission electron microscopy
Christian ONeil (Biophysics)
Abstract:
The conversion of specific intrinsically disordered proteins to β-sheet-rich fibrils is associated with many neurodegenerative diseases. Part of this conversion is the interaction between single protofilaments in which they wind together to form a mature fibril. By imaging with a tilted-beam Transmission Electron Microscope, mass-per-length measurements can determine the number of protofilaments making up any specific fibril. Here, we present a less cost-prohibitive method by utilizing a ThermoFisher Apreo LoVac Field Emission Scanning Electron Microscope equipped with a segmented STEM3 detector to image fibrils of the Y145STOP prion protein. By comparing the mass per length of samples containing various deletions in the flexible regions outside of the fibril core, we also provide analysis indicating that the measurements taken are sensitive to the size of disordered regions of the fibril being characterized. This method is shown to be an efficient and accurate way to determine the mass-per-length of fibrils as well as their composition of protofilaments.
References:
Chen B, Thurber KR, Shewmaker F, Wickner RB, Tycko R. Measurement of amyloid fibril mass-per-length by tilted-beam transmission electron microscopy. Proc Natl Acad Sci U S A. 2009 Aug 25;106(34):14339-44. doi: 10.1073/pnas.0907821106. Epub 2009 Aug 11. PMID: 19706519; PMCID: PMC2732815.
Theint T, Nadaud PS, Aucoin D, Helmus JJ, Pondaven SP, Surewicz K, Surewicz WK, Jaroniec CP. Species-dependent structural polymorphism of Y145Stop prion protein amyloid revealed by solid-state NMR spectroscopy. Nat Commun. 2017 Sep 29;8(1):753. doi: 10.1038/s41467-017-00794-z. PMID: 28963458; PMCID: PMC5622040.
Keywords: STEM, fibrils, prions