Amyloid β Conformation in Aqueous Environment

Amyloid β peptide (Aβ),42-residue peptide and its variations, is known to form amyloid fibrils in Alzheimer's disease. Solid-state NMR study reveals a parallel β-sheet structure in the Aβ fibrils. The atomic level structure of Aβ in aqueous environment, however, has not been determined, because of its tendency to aggregate. There are several reports that soluble forms of Aβ possess intrinsic neurotoxicity. It has recently become possible to determine the crystal structure of Aβ fragments in an aqueous solution without organic solvents and detergents using a fusion technique with a hyperthermophile protein. Aβ28-42 forms a β-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 Aβ conformation in aqueous environments and some viewpoints based on the knowledge.