Heme Binding Induces Dimerization and Nitration of Truncated β-Amyloid Peptide Aβ16 Under Oxidative Stress


  • The authors thank the Italian MIUR for support through the PRIN project, CIRCMSB, and COST CM1003. GT also thanks the COST CM1003 for an STSM fellowship. We also thank Davide Ciregna for assistance in peptide preparation.


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Stressful situation: 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.