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Micellar environments induce structuring of the N‐terminal tail of the prion protein
Author(s) -
Renner Christian,
Fiori Stella,
Fiorino Ferdinando,
Landgraf Dirk,
Deluca Dominga,
Mentler Matthias,
Grantner Klaus,
Parak Fritz G.,
Kretzschmar Hans,
Moroder Luis
Publication year - 2004
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.20015
Subject(s) - chemistry , micelle , biophysics , glycoprotein , crystallography , membrane , sequence (biology) , vesicle , stereochemistry , prion protein , molecule , c terminus , biochemistry , aqueous solution , amino acid , medicine , disease , organic chemistry , pathology , biology
In the physiological form, the prion protein is a glycoprotein tethered to the cell surface via a C‐terminal glycosylphosphatidylinositol anchor, consisting of a largely α‐helical globular C‐terminal domain and an unstructured N‐terminal portion. This unstructured part of the protein contains four successive octapeptide repeats, which were shown to bind up to four Cu 2+ ions in a cooperative manner. To mimic the location of the protein on the cell membrane and to analyze possible structuring effects of the lipid/water interface, the conformational preferences of a single octapeptide repeat and its tetrameric form, as well of the fragment 92–113, proposed as an additional copper binding site, were comparatively analyzed in aqueous and dodecylphosphocholine micellar solution as a membrane mimetic. While for the downstream fragment 92–113 no conformational effects were detectable in the presence of DPC micelles by CD and NMR, both the single octapeptide repeat and, in an even more pronounced manner, its tetrameric form are restricted into well‐defined conformations. Because of the repetitive character of the rigid structural subdomain in the tetrarepeat molecule, the spatial arrangement of these identical motifs could not be resolved by NMR analysis. However, the polyvalent nature of the repetitive subunits leads to a remarkably enhanced interaction with the micelles, which is not detectably affected by copper complexation. These results strongly suggest interactions of the cellular form of PrP (PrP c ) N‐terminal tail with the cell membrane surface at least in the octapeptide repeat region with preorganization of these sequence portions for copper complexation. There are sufficient experimental facts known that support a physiological role of copper complexation by the octapeptide repeat region of PrP c such as a copper‐buffering role of the PrP c protein on the extracellular surface. © 2004 Wiley Periodicals, Inc. Biopolymers, 2004