A Binuclear Zinc Interaction Fold Discovered in the Homodimer of Alzheimer's Amyloid-β Fragment with Taiwanese Mutation D7H.

Zinc-induced oligomerization of amyloid-β peptide (Aβ) produces potentially pathogenic agents of Alzheimer's disease. Mutations and modifications in the metal binding domain 1-16 of Aβ peptide crucially affect its zinc-induced oligomerization by changing intermolecular zinc mediated interface. The 3D structure of this interface appearing in a range of Aβ species is a prospective drug target for disease modifying therapy. Using NMR spectroscopy, EXAFS spectroscopy, mass spectrometry, and isothermal titration calorimetry the interaction of zinc ions with Aβ fragments 1-7 and 1-10 carrying familial Taiwanese mutation D7H was studied. Zinc ions induce formation of a stable homodimer formed by the two peptide chains fastened by two zinc ions and stacking interactions of imidazole rings. A binuclear zinc interaction fold in the dimer structure was discovered. It can be used for designing zinc-regulated proteins and zinc-mediated self-assembling peptides.