NR AOXY
AU Porquet,A.; Tournassat,C.; Charlet,L.; Chapron,Y.
TI Clay prion interaction (I).md simulation of the "unstructured tail" of prion in various environmental chemical composition. Preliminary work.
QU International Conference - Prion diseases: from basic research to intervention concepts - TSE-Forum, 08.10.-10.10.2003, Gasteig, München - Poster session - BR-07
PT Konferenz-Poster
AB Enzyme-clay interactions can modulate catalytic enzyme properties. The Molecular Dynamic simulation of enzyme adhesion on a clay cleavage surface of montmorillonite has shown that a mild physical chemistry interaction occurs. Water structure at the interface clay/water is more compact and polarized than in the bulk. This occurs with an important electric field, leading to a possible conformational change of the protein structure. As even stronger reactivity would be present on the lateral fracture of a solid clay particles, we examined if the interaction that can occur with an "unstructured tail" of a prion protein near these clay 'edge faces' with various metal ion compositions in an aqueous solution. Edge faces of the montmorillonite clay structure have been built. Many authors have worked on the octoreapet structure using several physical techniques converging to a coordination of the copper in each of the 4 sites. Recent structural data from Millhauser's team on the monomeric octorepet of the " unstructured tail" has shed new light on the site's structure. We have modified our MD simulation to include this new information. A quantum chemical approach was used to verify whether our MD calculation of the coordination shell for Mn and Cu ions, which indicated a swelling change from one ion to the other, was still justified. Actually, we found that the solvation cage of Cu2+ is swollen when Mn2+ exchanges places with copper, and during the oxidation of Mn2+ to Mn3+, the cage shrinks again. All of these conformational reorganizations could be one of the trigger mechanisms in forming the scrapie prion. A movie of the "dynamically structured octorepet" will be shown.
AD A. Porquet, C. Tournassat, L. Charlet, Y. Chapron, Alpine Institute of Environmental Dynamics, France
SP englisch
PO Deutschland