A rare occurrence of a β-turn in an amyloid βA4 peptide

✍ Scribed by Savita Tauro; Evans Coutinho; Sudha Srivastava

• Publisher: John Wiley and Sons
• Year: 2002
• Tongue: English
• Weight: 217 KB
• Volume: 40
• Category: Article
• ISSN: 0749-1581
• DOI: 10.1002/mrc.995

✦ Synopsis

Abstract

The fragment β(25–35) of the amyloid β‐peptide, like its parent βA4, has shown neurotrophic and late neurotoxic activities in cultured cells. The 3D structure of this important peptide was examined by ^1^H and ^13^C 2D‐NMR and MD simulations in DMSO‐d~6~ and water. The NMR parameters of chemical shift, ^3^J(N,Hα) coupling constants, temperature coefficients of NH chemical shifts and the pattern of intra and inter‐residue NOEs were used to deduce the structures. In DMSO‐d~6~, the peptide was found to take up a type I β‐turn around the C‐terminal residues Ile^8^–Gly^9^–Leu^10^–Met^11^, whereas in water at pH 5.5, it adopts a random coil conformation. This is only the second report of a β‐turn in the β‐amyloid class of peptides. The solution structures generated using restrained molecular dynamics were refined by MARDIGRAS to an R factor of 0.33 in the case of DMSO‐d~6~ and to 0.56 for water. Copyright © 2002 John Wiley & Sons, Ltd.