Dual regulation of cytosolic ascorbate peroxidase (APX) by tyrosine nitration and S-nitrosylation
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AuthorBegará Morales, Juan Carlos; Sánchez Calvo, Beatriz; Chaki, Mounira; Valderrama, Raquel; Mata-Pérez, Capilla; López Jaramillo, Javier; Padilla, María N.; Carreras, Alfonso; Corpas Aguirre, Francisco Javier; Barroso, Juan B.
Ascorbate peroxidaseNitrationNitric oxideS-NitrosoglutathioneS-nitrosylationPeroxynitriteReactive nitrogen speciesSalinity stress
Juan C. Begara-Morales, Beatriz Sánchez-Calvo, Mounira Chaki, Raquel Valderrama, Capilla Mata-Pérez, Javier López-Jaramillo, María N. Padilla, Alfonso Carreras, Francisco J. Corpas, Juan B. Barroso, Dual regulation of cytosolic ascorbate peroxidase (APX) by tyrosine nitration and S-nitrosylation, Journal of Experimental Botany, Volume 65, Issue 2, February 2014, Pages 527–538, [https://doi.org/10.1093/jxb/ert396]
SponsorshipSpanish Government; ERDF from the Ministry of Science and Innovation BIO2009-12003-C02-01 BIO2009-12003-C02-02 BIO2012-33904; Junta de Andalucia BIO286 BIO192; CICT of Universidad de Jaen (UJA, MINECO, Junta de Andalucia, FEDER)
Post-translational modifications (PTMs) mediated by nitric oxide (NO)-derived molecules have become a new area of research, as they can modulate the function of target proteins. Proteomic data have shown that ascorbate peroxidase (APX) is one of the potential targets of PTMs mediated by NO-derived molecules. Using recombinant pea cytosolic APX, the impact of peroxynitrite (ONOO–) and S-nitrosoglutathione (GSNO), which are known to mediate protein nitration and S-nitrosylation processes, respectively, was analysed. While peroxynitrite inhibits APX activity, GSNO enhances its enzymatic activity. Mass spectrometric analysis of the nitrated APX enabled the determination that Tyr5 and Tyr235 were exclusively nitrated to 3-nitrotyrosine by peroxynitrite. Residue Cys32 was identified by the biotin switch method as S-nitrosylated. The location of these residues on the structure of pea APX reveals that Tyr235 is found at the bottom of the pocket where the haem group is enclosed, whereas Cys32 is at the ascorbate binding site. Pea plants grown under saline (150mM NaCl) stress showed an enhancement of both APX activity and S-nitrosylated APX, as well as an increase of H2O2, NO, and S-nitrosothiol (SNO) content that can justify the induction of the APX activity. The results provide new insight into the molecular mechanism of the regulation of APX which can be both inactivated by irreversible nitration and activated by reversible S-nitrosylation.