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A rare occurrence of a β‐turn in an amyloid βA4 peptide
Author(s) -
Tauro Savita,
Coutinho Evans,
Srivastava Sudha
Publication year - 2002
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.995
Subject(s) - chemistry , peptide , random coil , turn (biochemistry) , residue (chemistry) , chemical shift , molecular dynamics , amyloid (mycology) , peptide fragment , stereochemistry , computational chemistry , biochemistry , circular dichroism , inorganic chemistry
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.