Amyloid fibrils are associated with many fatal degenerative

Amyloid fibrils are associated with many fatal degenerative diseases of humans and livestock. Livestock diseases such as scrapie in sheep and bovine spongiform encephalitis (BSE, or mad cow disease) have major negative impacts on agriculture. Human diseases characterized by amyloid fibrils include Alzheimer\\\'s disease and Creutzfeldt-Jakob disease. The images below show a short segment of a typical amyloid fibril. The image on the left shows the side chains protruding from the faces of the -sheets. Choose the true statements about amyloid fibrils.

Some amyloid fibrils are formed from proteolytic fragments that self-assemble into extended -sheet structures.

Proteins that form amyloid fibrils are normally soluble.

Proteins that convert to an amyloid structure form soluble fibrils.

Nucleation of amyloid structure may be triggered when two -sheet regions from two partially folded proteins associate.

Amyloid fibrils have a high amount of -helical structure.

Solution

Answer:

There are three major classes of secretase enzymes have been reported which Cleve amyloid fibril into its pathogenic oligomer. These enzymes are alpha, beta and gamma secretase. So, the statement \'some amyloid fibrils are formed proteolytic fragments that that self self assemble into extended b-sheet structures\' is true. Generally amyloid proteins are generated from Amyloid precursor protein (APP) which is trans membrane by nature. Cleaved amyloid fibrils are soluble but further oligomerization and complex fibrillar aggregation of amyloid is insoluble and prone to toxicity. So, \'Proteins that form amyloid fibrils are normally soluble\' is not completely true. Further, Nucleation of amyloid structure may be triggered when two -sheet regions from two partially folded proteins associate statement is true.Amyloid fibrils have a high amount of -helical structure. Is false statement. beta plated sheet is abundant in the same.