New Structural Approaches to Understand the Disease Related Forms of the Prion Protein
Annual rept. 15 Jun 2004-14 Jun 2005
CALIFORNIA UNIV BERKELEY
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Expression in E.coli and purification of a prion protein peptide residues 89-143 with a PlOlL mutation, designated P55, that has shown biological activity, has been done. Isotope labeling and solid state NMR with peptide produced in this was has been demonstrated, enabling further work to define the conformation of the infectious, fibrillar form. Fully C13N15 labeled peptide was also produced and resonances in solution assigned to enable NMR detected hydrogen exchange of fibrils to be done. Mass spectroscopy detection of hydrogen exchange has also been pursued but conditions for fragmentation need to be further refined. The combination of solid state NMR and hydrogen exchange are being used to define conformations and interactions of the peptide backbone that will lead to a model for P55 in the fibril state. The kinetics of the fibrillization process of the P55 peptide have been studied to optimize conditions for fibril formation, and to enable comparison of initial small fibrils with larger mature ones.