info:eu-repo/semantics/article
Exploring the molecular basis of human manganese superoxide dismutase inactivation mediated by tyrosine 34 nitration
Fecha
2011-03Registro en:
Moreno, Diego Martin; Marti, Marcelo Adrian; de Biase, Pablo Martin; Estrin, Dario Ariel; Demicheli, Verónica; et al.; Exploring the molecular basis of human manganese superoxide dismutase inactivation mediated by tyrosine 34 nitration; Elsevier Science Inc; Archives of Biochemistry and Biophysics; 507; 2; 3-2011; 304-309
0003-9861
CONICET Digital
CONICET
Autor
Moreno, Diego Martin
Marti, Marcelo Adrian
de Biase, Pablo Martin
Estrin, Dario Ariel
Demicheli, Verónica
Radi, Rafael
Boechi, Leonardo
Resumen
Manganese Superoxide Dismutase (MnSOD) is an essential mitochondrial antioxidant enzyme that protects organisms against oxidative damage, dismutating superoxide radical (O2-) into H2O2 and O2. The active site of the protein presents a Mn ion in a distorted trigonal-bipyramidal environment, coordinated by H26, H74, H163, D159 and one -OH ion or H2O molecule. The catalytic cycle of the enzyme is a "ping-pong" mechanism involving Mn3+/Mn2+. It is known that nitration of Y34 is responsible for enzyme inactivation, and that this protein oxidative modification is found in tissues undergoing inflammatory and degenerative processes. However, the molecular basis about MnSOD tyrosine nitration affects the protein catalytic function is mostly unknown. In this work we strongly suggest, using computer simulation tools, that Y34 nitration affects protein function by restricting ligand access to the active site. In particular, deprotonation of 3-nitrotyrosine increases drastically the energetic barrier for ligand entry due to the absence of the proton. Our results for the WT and selected mutant proteins confirm that the phenolic moiety of Y34 plays a key role in assisting superoxide migration. © 2010 Elsevier Inc. All rights reserved.