NR AODA
AU Kuroda,Y.; Maeda,Y.; Sawa,S.; Shibata,K.; Miyamoto,K.; Nakagawa,T.
TI Effects of detergents on the secondary structures of prion protein peptides as studied by CD spectroscopy
QU Journal of Peptide Science : an Official Publication of the European Peptide Society 2003 Apr; 9(4): 212-20
PT journal article
AB Pathogenic prion proteins (PrPsc) are thought to be produced by alpha-helical to beta-sheet conformational changes in the normal cellular prion proteins (PrPc) located solely in the caveolar compartments. In order to inquire into the possible conformational changes due to the influences of hydrophobic environments within caveolae, the secondary structures of prion protein peptides were studied in various kinds of detergents by CD spectra. The peptides studied were PrP(129-154) and PrP(192-213); the former is supposed to assume beta-sheets and the latter alpha-helices, in PrPsc. The secondary structure analyses for the CD spectra revealed that in buffer solutions, both PrP(129-154) and PrP(192-213) mainly adopted random-coils (approximately 60%), followed by beta-sheets (30%-40%). PrP(129-154) showed no changes in the secondary structures even in various kinds of detergents such as octyl-beta-D-glucopyranoside (OG), octy-beta-D-maltopyranoside (OM). sodium dodecyl sulfate (SDS), Zwittergent 3-14 (ZW) and dodecylphosphocholine (DPC). In contrast, PrP(192-213) changed its secondary structure depending on the concentration of the detergents. SDS, ZW, OG and OM increased the alpha-helical content, and decreased the beta-sheet and random-coil contents. DPC also increased the alpha-helical content, but to a lesser extent than did SDS, ZW, OG or OM. These results indicate that PrP(129-154) has a propensity to adopt predominantly beta-sheets. On the other hand, PrP(192-213) has a rather fickle propensity and varies its secondary structure depending on the environmental conditions. It is considered that the hydrophobic environments provided by these detergents may mimic those provided by gangliosides in caveolae, the head groups of which consist of oligosaccharide chains containing sialic acids. It is concluded that PrPc could be converted into a nascent PrPsc having a transient PrPsc like structureunder the hydrophobic environments produced by gangliosides.
MH Ammonium Compounds/pharmacology; Animals; Circular Dichroism; Detergents/*pharmacology; Hamsters; Hydrophobicity; Mesocricetus; Peptide Fragments/*chemistry; Phosphorylcholine/*analogs & derivatives/pharmacology; Prions/*chemistry; Protein Structure, Secondary/drug effects; Sodium Dodecyl Sulfate/pharmacology
AD Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto, 606-8501, Japan. yokuroda@pharm.kyoto-u.ac.jp
SP englisch
PO England