Interaction of a Recombinant Prion Protein with Organo-Mineral Complexes as Assessed by FT-IR and CPMAS 13C NMR Analysis

Abstract

Prion proteins are considered as the main agents for the Transmissible Spongiform Encephalopathies (TSE). The misfolded form, PrP Sc , which is also indicated as the etiological agent for TSE, exhibits high resistance to degradation in environmental processes. Soil contamination by prion proteins is a real environmental issue since contaminated soils can become potential reservoir and diffuser for TSE infectivity. In this work, the interaction of prion protein with organo- mineral complexes was studied by using a recombinant non pathogenic prion protein and a model soil system. This latter was represented by a soil manganese mineral coated with polymerized catechol. FT-IR spectra showed amide I and II sig- nals which revealed protein involvement in catechol polymers coating manganese oxide surface. CPMAS 13 C-NMR was applied to follow the complexation of the protein to the soil-like system. All the signals were attributed to C-N in peptidic bonds, alkyl chains and methyl groups. The NMR spectrum of the prion protein interacting directly with birnessite re- vealed disappearance of signals due to the paramagnetic nature of manganese oxide or protein abiotic degradation, while the presence of organic matter strongly reduced the disappearance of prion protein signals.