Amyloid beta conformation in aqueous environment

Amyloid beta peptide (Abeta), 42-residue peptide and its variations, is known to form amyloid fibrils in Alzheimer's disease. Solid-state NMR study reveals a parallel beta-sheet structure in the Abeta fibrils. The atomic level structure of Abeta in aqueous environment, however, has not been determined, because of its tendency to aggregate. There are several reports that soluble forms of Abeta possess intrinsic neurotoxicity. It has recently become possible to determine the crystal structure of Abeta fragments in an aqueous solution without organic solvents and detergents using a fusion technique with a hyperthermophile protein. Abeta28-42 forms a beta-conformation. This fusion technique enables us to obtain structural information at atomic resolution for amyloidogenic peptides in aqueous environments. This review describes our current knowledge on the Abeta conformation in aqueous environments and some viewpoints based on the knowledge.