NMR Studies of the Zn2+ Interactions with Rat and Human β-Amyloid (1-28) Peptides in Water-Micelle Environment

Alzheimer's disease is a fatal neurodegenerative disorder involving the abnormal accumulation and deposition of peptides (amyloid-beta, A beta) derived from the amyloid precursor protein. Here, we present the structure and the Zn(2+) binding sites of human and rat A beta(1 -28) fragments in water/sodium dodecyl sulfate (SDS) micelles by using (1)H NMR spectroscopy. The chemical shift variations measured after Zn(2+) addition at T > 310 K allowed us to assign the binding donor atoms in both rat and human zinc complexes. The Asp-1 amine, His-6 N delta, Glu-11 COO(-), and His-13 N epsilon of rat A beta(28) all enter the metal coordination sphere, while His-6 N delta, His-13, His-14 N epsilon, Asp-1 amine, and/or Glu-11 COO(-) are all bound to Zn(2+) in the case of human A beta(28). Finally, a comparison between the rat and human binding abilities was discussed.