Heme binding induces dimerization and nitration of truncated β-amyloid peptide Aβ16 under oxidative stress

Ferric heme binds to Aβ16 giving a mixture of five-coordinate [hemin(Aβ16)] and six-coordinate [hemin(Aβ16)2] species, the equilibrium of which depends on the Aβ16/hemin ratio and on temperature. Under oxidative and nitrative stress conditions the heme-Aβ16 complexes promote peroxidase-like reactions causing oxidation and nitration of the Aβ Tyr10 residue. Both dityrosine formation and tyrosine nitration strongly enhance Aβ aggregation.