title: Intermolecular alignment in β2-microglobulin amyloid fibrils.
abstract: 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 (15)N-(13)C MAS NMR correlation spectroscopy. We utilize a fibril sample grown from a 50:50 mixture of (15)N,(12)C- and (14)N,(13)C-labeled β2m monomers, the latter prepared using 2-(13)C glycerol as the carbon source. Together with the use of ZF-TEDOR mixing, this sample allowed us to observe intermolecular (15)N-(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.
authors.affiliation: Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Galia T
authors.initials: GT
authors.lastname: Debelouchina
authors.forename: Geoffrey W
authors.initials: GW
authors.lastname: Platt
authors.forename: Marvin J
authors.initials: MJ
authors.lastname: Bayro
authors.forename: Sheena E
authors.initials: SE
authors.lastname: Radford
authors.forename: Robert G
authors.initials: RG
authors.lastname: Griffin
mesh_terms: D000682:Amyloid / Q000737:chemistry*; D008958:Models, Molecular; D019906:Nuclear Magnetic Resonance, Biomolecular; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D001613:beta 2-Microglobulin / Q000737:chemistry*
chemical_list: D000682:Amyloid; D001613:beta 2-Microglobulin