Site-specific detection of protein secondary structure using 2D IR dihedral indexing: a proposed assembly mechanism of oligomeric hIAPP.

ABSTRACT: Human islet amyloid polypeptide (hIAPP) aggregates into fibrils through oligomers that have been postulated to contain α-helices as well as β-sheets. We employ a site-specific isotope labeling strategy that is capable of detecting changes in dihedral angles when used in conjunction with 2D IR spectroscopy. The method is analogous to the chemical shift index used in NMR spectroscopy for assigning protein secondary structure. We introduce isotope labels at two neighbouring residues, which results in an increased intensity and positive frequency shift if those residues are α-helical versus a negative frequency shift in β-sheets and turns. The 2D IR dihedral index approach is demonstrated for hIAPP in micelles for which the polypeptide structure is known, using pairs of ¹³C

SUBMITTER: Maj M 

PROVIDER: S-EPMC5868010 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature