Copper(II)-bis-histidine coordination structure in a fibrillar amyloid β-peptide fragment and model complexes revealed by electron spin echo envelope modulation spectroscopy.

ABSTRACT: Truncated and mutated amyloid-β (Aβ) peptides are models for systematic study-in homogeneous preparations-of the molecular origins of metal ion effects on Aβ aggregation rates, types of aggregate structures formed, and cytotoxicity. The 3D geometry of bis-histidine imidazole coordination of Cu(II) in fibrils of the nonapetide acetyl-Aβ(13-21)H14A has been determined by powder (14) N electron spin echo envelope modulation (ESEEM) spectroscopy. The method of simulation of the anisotropic combination modulation is described and benchmarked for a Cu(II) -bis-cis-imidazole complex of known structure. The revealed bis-cis coordination mode, and the mutual orientation of the imidazole rings, for Cu(II) in Ac-Aβ(13-21)H14A fibrils are consistent with the proposed β-sheet structural model and pairw

SUBMITTER: Hernandez-Guzman J 

PROVIDER: S-EPMC3864031 | biostudies-literature | 2013 Sep

REPOSITORIES: biostudies-literature