NR AXNT
AU Hafner Bratkovic,I.; Gaspersic,J.; Japelj,B.; Vorberg,I.; Jerala,R.
TI Disulfide Tethers Give New Insight into The Prion Protein Conformational Change
QU International Conference - Prion 2007 (26.-28.9.2007) Edinburgh International Conference Centre, Edinburgh, Scotland, UK - Book of Abstracts: Protein Misfolding P01.32
IA http://www.prion2007.com/pdf/Prion Book of Abstracts.pdf
PT Konferenz-Poster
AB Prion diseases are neurodegenerative diseases that effect people and animals. Prion hypothesis states that infectious agent is composed of protein only and does not contain nucleic acids as do conventional pathogens. In the course of the disease the native cellular prion protein in the presence of the infectious prion converts from the mainly alpha helical into the insoluble beta sheet amyloid form called PrPsc. The high resolution structure of PrPsc is not known, so it is very difficult to propose the mechanism of conformational change. The knowledge on this structural transformation is important for the understanding of the pathology of the disease as well for the design of possible therapies. Our approach to map the structure of the converted PrP (prion protein) was to restrict the different structural segments of PrP by covalent links, preventing the structural transition of the defined segments of the structure. We have selected the sites of introduced disulfides based on the three dimensional structure of mouse prion protein. It is expected that introduction of additional disulfides would stabilize the structure and also make it more rigid, but its influence on the replication should be position dependent. We have introduced two types of disulfides - shortrange mutants, placed in the three surface loops between the elements of the regular secondary structure and long-range mutants, with disulfide bridges enclosing several secondary structure elements. We confirmed correct folding of the mutants by circular dichroism and nuclear magnetic resonance spectra of the isolated proteins. Most short range mutants show comparable thermodynamic stability to the wild-type, while long range and some short-range mutants are significantly more stable than the wild-type protein. We also followed in vitro fibrilization of mutants. We discovered that there is no correlation between the protein stability and structural conversion, which allows us to map the structural segments of PrP structure important for the conformational change. Our model provides structural information for the improvement of the model of conformational transition.
AD I. Hafner Bratkovic, J. Gaspersic, B. Japelj, R. Jerala, National Institute of Chemistry, Department of Biotechnology, Slovenia; I. Vorberg, Technical University Munich, Institute of Virology, Germany
SP englisch
PO Schottland