NR AXXI
AU Tabrett,C.; Hardy,T.; Hill,A.; Schmidt,B.; Hogg,P.
TI Disulfide Bond Switching in the Prion Protein
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Protein Misfolding P01.08
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB
Background: The prion protein contains a single disulfide bond in the hydrophobic interior of the protein. There is a considerable body of circumstantial evidence that the bond is cleaved and then reforms when the protein transitions from the normal to the scrapie structure. The mechanism of cleavage of the bond is unknown.
Aims: All available NMR structures of prion protein were analysed to determine if there are any structural features that would predispose the disulfide bond to cleavage. The C179-C214 disulfide bond was found to exist predominantly in either a low energy configuration that is inaccessible to solvent or a high energy configuration that is accessible to solvent. Accessibility of solvent to the disulfide is governed by the positioning of three aromatic residues in the vicinity of the bond; Y162, F176 and Y216. We hypothesized that replacing these aromatic residues with alanine, a neutral amino acid, would increase the rate of cleavage of the disulfide and conversion to the scrapie form.
Methods: Wild type or mutant full length recombinant murine prion protein was produced in E. coli and purified to homogeneity. Y162, F176 and Y216 were mutated to alanine individually or in combination. Stability of the purified proteins was monitored in the absence or presence of copper.
Results: Replacement of Y162, F176 and/or Y216 with alanine decreased the stability of the protein.
Discussion: Our findings imply that accessibility of solvent to the prion disulfide is controlled by the positions of three aromatic residues nearby the bond.
Conclusion: The prion disulfide bond exists in either a low energy configuration that is inaccessible to solvent or a high energy configuration that is accessible to solvent. We suggest that switching of the prion disulfide from the low to high energy form is an early event in conversion to the scrapie structure.
AD C. Tabrett, T. Hardy, B. Schmidt, P. Hogg, University of New South Wales, Centre for Vascular Research, Australia; A. Hill, Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Department of Biochemistry and Molecular Biology, Australia
SP englisch
PO Schottland
EA pdf-Datei und Poster, (Titel: Structural Properties of the Prion Protein Disulfide)