Surface characterization of insulin protofilaments and fibril polymorphs using tip-enhanced Raman spectroscopy (TERS).

ABSTRACT: Amyloid fibrils are β-sheet-rich protein aggregates that are strongly associated with a variety of neurodegenerative maladies, such as Alzheimer's and Parkinson's diseases. Even if the secondary structure of such fibrils is well characterized, a thorough understanding of their surface organization still remains elusive. Tip-enhanced Raman spectroscopy (TERS) is one of a few techniques that allow the direct characterization of the amino acid composition and the protein secondary structure of the amyloid fibril surface. Herein, we investigated the surfaces of two insulin fibril polymorphs with flat (flat) and left-twisted (twisted) morphology. It was found that the two differ substantially in both amino acid composition and protein secondary structure. For example, the amounts of Tyr, Pro, a

SUBMITTER: Kurouski D 

PROVIDER: S-EPMC3907223 | biostudies-literature | 2014 Jan

REPOSITORIES: biostudies-literature