Sequence and structure-based peptides as potent amyloid inhibitors: A review

Misfolded and natively disordered globular proteins tend to aggregate together in an interwoven fashion to form fibrous, proteinaceous deposits referred to as amyloid fibrils. Formation and deposition of such insoluble fibrils are the characteristic features of a broad group of diseases, known as amyloidosis. Some of these proteins are known to cause several degenerative disorders in humans, such as Amyloid-Beta (A beta) in Alzheimer's disease (AD), human Islet Amyloid Polypeptide (hIAPP, amylin) in type 2 diabetes, alpha-synuclein (alpha-syn) in Parkinson's disease (PD) and so on. The fact that these proteins do not share any significant sequence or structural homology in their native states make therapy quite challenging. However, it is observed that aggregation-prone proteins and peptides tend to adopt a similar type of secondary structure during the formation of fibrils. Rationally designed peptides can be a potent inhibitor that has been shown to disrupt the fibril structure by binding specifically to the amyloidogenic region(s) within a protein. The following review will analyze the inhibitory potency of both sequence-based and structure-based small peptides that have been shown to inhibit amyloidogenesis of proteins such as A beta, human amylin, and alpha-synuclein.