New isolated or recombinant or engineered variant beta-2-microglobulin polypeptide which is amyloidogenic under essentially physiological conditions in vitro, used e.g. to study amyloid fibrillogenesis to treat e.g. Alzheimer's disease

NOVELTY - Isolated or recombinant or engineered variant beta -2-microglobulin ( beta 2M) polypeptide (P1) which is amyloidogenic under essentially physiological conditions in vitro, is new. USE - The isolated or recombinant or engineered variant beta 2M polypeptide (P1) is useful for: forming variant beta 2M amyloid fibrils in vitro (claimed); and studying amyloid fibrillogenesis, including diagnostic and therapeutic applications which is useful for treating Alzheimer's disease, type 2 diabetes, Parkinson's disease and Huntington's disease. No biological data given. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) a polypeptide having at least 95% identity with the polypeptide (P1); (2) a nucleic acid molecule encoding the polypeptide (P1); (3) a recombinant vector expressing the nucleic acid molecules; (4) a host cell expressing the vector; (5) a host cell expressing the plasmid; (6) a composition comprising the polypeptide (P1); (7) a method (M1) of forming variant beta 2M amyloid fibrils in vitro, comprising: adding an isolated or recombinant or engineered variant beta 2M polypeptide (P1) to a solution under essentially physiological conditions; incubating the solution at 37 degrees C, where variant beta 2M amyloid fibrils are formed; and determining that the variant beta 2M amyloid fibrils formed specifically bind Congo red from an alkaline alcoholic solution and then show red/green birefringence when viewed under crossed polarized light; and (8) a method (M2) of testing whether a compound or composition inhibits variant beta 2M amyloid formation, comprising: adding an isolated or recombinant or engineered variant beta 2M polypeptide (P1) to a solution under essentially physiological conditions; incubating the solution at 4-37 degrees C where variant beta 2M amyloid fibrils are formed; adding the compound or composition to the variant beta 2M amyloid fibrils; and determining whether the compound or composition inhibits the formation of variant beta 2M amyloid fibrils.