Intermolecular Alignment in Beta 2-Microglobulin Amyloid Fibrils

• Main Authors: Debelouchina, Galia Tzvetanova (Contributor), Bayro, Marvin J. (Contributor), Radford, Sheena E. (Author), Griffin, Robert Guy (Contributor), Platt, Geoffrey W. (Author)
• Other Authors: Massachusetts Institute of Technology. Department of Chemistry (Contributor), Francis Bitter Magnet Laboratory (Massachusetts Institute of Technology) (Contributor)
• Format: Article
• Language: English
• Published: American Chemical Society (ACS), 2012-08-07T18:27:38Z.
• Subjects: Article
• Online Access: Get fulltext

 The deposition of amyloid-like fibrils, composed primarily of the 99-residue protein β2-microglobulin (β2m), is one of the characteristic symptoms of dialysis-related amyloidosis. Fibrils formed in vitro at low pH and low salt concentration share many properties with the disease related fibrils and have been extensively studied by a number of biochemical and biophysical methods. These fibrils contain a significant β-sheet core and have a complex cryoEM electron density profile. Here, we investigate the intrasheet arrangement of the fibrils by means of [superscript 15]N−[superscript 13]C MAS NMR correlation spectroscopy. We utilize a fibril sample grown from a 50:50 mixture of [superscript 15]N,[superscript 12]C- and [superscript 14]N,[superscript 13]C-labeled β2m monomers, the latter prepared using 2-[superscript 13]C glycerol as the carbon source. Together with the use of ZF-TEDOR mixing, this sample allowed us to observe intermolecular [superscript 15]N−[superscript 13]C backbone-to-backbone contacts with excellent resolution and good sensitivity. The results are consistent with a parallel, in-register arrangement of the protein subunits in the fibrils and suggest that a significant structural reorganization occurs from the native to the fibril state.