Abstracts Book - IMRC 2018

• SB2-P022
THE INFLUENCE OF MEMBRANE MODEL AT PRION AGGREGATION,
A LANGMUIR ESSAYS AND INFRARED CHARACTERIZATION
Bianca Sandrino 1 , Karen Jochelavicius 1 , Diogo Volpati 2 , Simone Barbosa 1 , Tathyane M. Nobre 1 ,
Osvaldo Novais de Oliveira Jr. 1
1
Universidade de São Paulo, São Carlos Institute of Physics, Brazil. 2 Mid Sweden University,
Department of Natural Sciences, Sweden.
Protein aggregation through b-sheet rich secondary structures is associated
with various neurodegenerative diseases, including Alzheimer’s, Huntington’s
and spongiform encephalopathy. In this study, we investigate the aggregation
behavior of the protein fragment 106-127 (referred to as Pr106-127), known to
be involved in triggering these diseases, upon interacting with cell membrane
models represented by Langmuir monolayers. The lipids used to form such
monolayers were 2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), typical of
healthy mammalian cells, and a brain total lipid extract (BTLE). Neat Pr106-127
formed Langmuir monolayers in which it adopted mainly b-sheet conformation,
according to data polarization-modulated infrared reflection absorption
spectroscopy (PM-IRRAS). This predominance of b-sheet secondary structure
also applied to mixed monolayers and deposited Langmuir-Blodgett (LB) films
of Pr106-127 and BTLE, thus pointing to possible formation of protein fibrils. In
contrast, some degree of α-helix structure for Pr106-127 was observed for
mixed Langmuir monolayers with DOPC. In addition to confirming the
importance of lipid composition for the interaction of proteins, the results
presented here are consistent with the expected fibrillary structures for Pr106-
127 interacting with brain cell lipids.
Acknowledgment:
This work was supported by FAPESP (2013/14262-7 and 2014/12567-8), INEO,
CNPq and CAPES (Brazil).
Keywords: Prion peptide, Langmuir films as celular membrane model, Infrared
characterization
Presenting authors email: biancasandrino@yahoo.com.br