Bovine insulin filaments induced by reducing disulfide bonds show a different morphology, secondary structure, and cell toxicity from intact insulin amyloid fibrils.

ABSTRACT: Amyloid fibrils are associated with more than 20 diseases, including Alzheimer's disease and type II diabetes. Insulin is a 51-residue polypeptide hormone, with its two polypeptide chains linked by one intrachain and two interchain disulfide bonds, and has long been known to self-assemble in vitro into amyloid fibrils. We demonstrate here that bovine insulin forms flexible filaments in the presence of a reducing agent, Tris (2-carboxyethyl) phosphine. The insulin filaments, possibly formed due to partial reduction of S-S bonds in insulin molecules, differ from intact insulin fibrils in terms of their secondary structure. The insulin filaments were determined to have an antiparallel beta-sheet structure, whereas the insulin fibrils have a parallel beta-sheet structure. Of importance, the ce

SUBMITTER: Zako T 

PROVIDER: S-EPMC2718267 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature