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Polymers and Self Assembly: From Biology to Nanomaterials Poster Session II
47-POS
Board 47
Dissection of Prion protein and Lipid Interaction
Raiane Santos
2
, Quezia Tedeschi
1
, Jerson Silva
2
,
Tuane Vieira
1
.
1
IFRJ, Rio de Janeiro, Brazil,
2
UFRJ, Rio de Janeiro, Brazil.
Introduction: Transmissible spongiform encephalopathies are a group of fatal diseases, which
affect mammals, caused by an abnormal isoform of the prion protein (PrP). Conversion of
cellular PrP (PrPC) into the pathological conformer, PrPSc, involves contact between both
isoforms and probably requires a cellular factor. Recombinant PrP can be converted to an
abnormal form via seeded polymerization in vitro techniques in the presence of lipids.
Objectives: The importance of lipid molecules for conversion has been revealed, but little is
known about the structural features implicit in this interaction. A detailed understanding of this
interaction may provide new insights into toxic mechanisms associated with this disease.
Material and Methods: In the present work, we used light scattering, FTIR, electron microscopy
and fluorescence measurements in order to provide information on the chemical and physical
properties of the murine recombinant PrP (rPrP 23-231) interaction with
Phosphatidylethanolamine (PE) and Phosfatidic Acid (PA) vesicles. Results and Discussion: We
found that phospholipid vesicles raised rPrP light scattering. PE induced changes on PrPC
secondary structure, forming soluble oligomers/aggregates with increased β-sheet. PA induced
changes on PrPC secondary structure, forming insoluble aggregates. These aggregates were
shown to be fibers with increased β-sheet content. Conclusions: Our results suggest that
phospholipids, such as PE and PA, play a role in prion aggregation, acting as a cofactor for its
pathogenic conformation. On the other hand, these two lipids seem to trigger PrPC aggregation
through different pathways, generating different PrPC aggregated forms. These differences may
be also important for disease development.