Supramolecular structure in full-length Alzheimer's beta-amyloid fibrils: evidence for a parallel beta-sheet organization from solid-state nuclear magnetic resonance.
We report constraints on the supramolecular structure of amyloid fibrils formed by the 40-residue beta-amyloid peptide associated with Alzheimer's disease (A beta(1-40)) obtained from solid-state nuclear magnetic resonance (NMR) measurements of intermolecular dipole-dipole couplings between (13)C labels at 11 carbon sites in residues 2 through 39. The measurements are carried out under magic-angle spinning conditions, using the constant-time finite-pulse radiofrequency-driven recoupling (fpRFDR-CT) technique. We also present one-dimensional (13)C magic-angle spinning NMR spectra of the labeled A beta(1-40) samples. The fpRFDR-CT data reveal nearest-neighbor intermolecular distances of 4.8 +/- 0.5 A for carbon sites from residues 12 through 39, indicating a parallel alignment of neighboring peptide chains in the predominantly beta-sheet structure of the amyloid fibrils. The one-dimensional NMR spectra indicate structural order at these sites. The fpRFDR-CT data and NMR spectra also indicate structural disorder in the N-terminal segment of A beta(1-40), including the first nine residues. These results place strong constraints on any molecular-level structural model for full-length beta-amyloid fibrils.
Laboratory of Chemical Physics, the National Institute of Diabetes and Digestive and Kidney Diseases, the National Institutes of Health, Bethesda, Maryland 20892-0520 USA.
John J
JJ
Balbach
Aneta T
AT
Petkova
Nathan A
NA
Oyler
Oleg N
ON
Antzutkin
David J
DJ
Gordon
Stephen C
SC
Meredith
Robert
R
Tycko
D000544:Alzheimer Disease / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000737:chemistry* / Q000378:metabolism; D002244:Carbon / Q000737:chemistry; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D010452:Peptide Biosynthesis; D010455:Peptides / Q000737:chemistry; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary
D016229:Amyloid beta-Peptides; D010455:Peptides; D002244:Carbon