Two-dimensional IR spectroscopy and segmental 13C labeling reveals the domain structure of human γD-crystallin amyloid fibrils.

ABSTRACT: The structural eye lens protein γD-crystallin is a major component of cataracts, but its conformation when aggregated is unknown. Using expressed protein ligation, we uniformly (13)C labeled one of the two Greek key domains so that they are individually resolved in two-dimensional (2D) IR spectra for structural and kinetic analysis. Upon acid-induced amyloid fibril formation, the 2D IR spectra reveal that the C-terminal domain forms amyloid β-sheets, whereas the N-terminal domain becomes extremely disordered but lies in close proximity to the β-sheets. Two-dimensional IR kinetics experiments show that fibril nucleation and extension occur exclusively in the C-terminal domain. These results are unexpected because the N-terminal domain is less stable in the monomer form. Isotope dilution exp

SUBMITTER: Moran SD 

PROVIDER: S-EPMC3295317 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature