ORGN 734 |
| Fatma Eker, Department of Biology (Eker)/Department of Chemistry (Schweitzer-Stenner), Drexel University, 32nd and Chestnut Streets, Philadelphia, PA 19104, Kai Griebenow, Department of Chemistry, University of Puerto Rico, Rio Piedras Campus, San Juan, PR 00931, and Reinhard Schweitzer-Stenner, Department of Chemistry, Drexel University, 3141 Chestnut Streets, Philadelphia, PA 19104. |
| The formation of amyloid plaques is generally described in terms of an α-helix ↔β-sheet transition. The β-sheet is considered as a misfolded state of the respective protein or peptide. Presently available data suggest that the situation is different for the amyloid peptide Aβ1-42 which adopts a helical conformation only in the presence of a stabilizing environment like charged vesicles or ,2,2-trifluoroethanol (TFE). In an aqueous solution the monomer of this peptide is generally ascribed as random coil. However, recent investigations of the model fragment Aβ1-28 revealed a substantial PPII fraction (Eker et al., Biochemistry, in press) at acidic conditions. This seems to indicate that PPII rather than the α-helical conformation must be considered as the peptide’s natural state. However, this notion is contested by electronic CD-measurements on Aβ1-28 at alkaline pH, which reveals an α-helix formation at higher temperatures. At physiological temperatures the sample already shows a mixture of α- and PPII helical conformations suggesting that Aβ-peptides can form an α-helix even in the absence of a helix stabilizing environment. |
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Proteins, Peptides, and Amino Acids
8:00 AM-12:00 PM, Thursday, August 26, 2004 Pennsylvania Convention Center -- 201A, Oral
Division of Organic Chemistry |