Neutron Reflectometry Studies Define Prion Protein N-terminal Peptide Membrane Binding

Anton Le Brun, Cathryn Louise Haigh, Simon Drew, Michael James, Martin Boland, Steven John Collins

Research output: Contribution to journalArticle

Abstract

The prion protein (PrP), widely recognized to misfold into the causative agent of the transmissible spongiform encephalopathies, has previously been shown to bind to lipid membranes with binding influenced by both membrane composition and pH. Aside from the misfolding events associated with prion pathogenesis, PrP can undergo various posttranslational modifications, including internal cleavage events. Alpha- and beta-cleavage of PrP produces two N-terminal fragments, N1 and N2, respectively, which interact specifically with negatively charged phospholipids at low pH. Our previous work probing
N1 and N2 interactions with supported bilayers raised the possibility that the peptides could insert deeply with minimal disruption. In the current study we aimed to refine the binding parameters of these peptides with lipid bilayers. To this end, we used neutron reflectometry to define the structural details of this interaction in combination with quartz crystal microbalance interrogation.
Neutron reflectometry confirmed that peptides equivalent to N1 and N2 insert into the interstitial space between the phospholipid headgroups but do not penetrate into the acyl tail region. In accord with our previous studies, interaction was stronger for the N1fragment than for the N2, with more peptide bound per lipid. Neutron reflectometry analysis also detected lengthening of the lipid acyl tails, with a concurrent decrease in lipid area. This was most evident for the N1 peptide and suggests an induction of increased lipid order in the absence of phase transition. These observations stand in clear contrast to the findings of analogous studies of Ab and a-synuclein and thereby support the possibility of a functional role for such N-terminal fragment-membrane
interactions.
Original languageEnglish
Pages (from-to)2313-2324
Number of pages12
JournalBiophysical Journal
Volume107
Issue number10
DOIs
Publication statusPublished - 2014
Externally publishedYes

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  • Cite this

    Le Brun, A., Haigh, C. L., Drew, S., James, M., Boland, M., & Collins, S. J. (2014). Neutron Reflectometry Studies Define Prion Protein N-terminal Peptide Membrane Binding. Biophysical Journal, 107(10), 2313-2324. https://doi.org/10.1016/j.bpj.2014.09.027