Begara-Morales, Juan CarlosSánchez-Calvo, BeatrizGómez-Rodríguez, María VictoriaChaki, MouniraValderrama, RaquelMata-Pérez, CapillaLópez-Jaramillo, Francisco JavierCorpas, Francisco JavierBarroso-Albarracín, Juan Bautista2025-01-072025-01-072019-10-01Antioxidants 2019, 8, 4482076-3921doi:10.3390/antiox8100448https://hdl.handle.net/10953/3715Low temperature (LT) negatively a ects plant growth and development via the alteration of the metabolism of reactive oxygen and nitrogen species (ROS and RNS).AmongRNS, tyrosine nitration, the addition of an NO2 group to a tyrosine residue, can modulate reduced nicotinamide-dinucleotide phosphate (NADPH)-generating systems and, therefore, can alter the levels of NADPH, a key cofactor in cellular redox homeostasis. NADPH also acts as an indispensable electron donor within a wide range of enzymatic reactions, biosynthetic pathways, and detoxification processes, which could a ect plant viability. To extend our knowledge about the regulation of this key cofactor by this nitric oxide (NO)-related post-translational modification, we analyzed the e ect of tyrosine nitration on another NADPH-generating enzyme, the NADP-malic enzyme (NADP-ME), under LT stress. In Arabidopsis thaliana seedlings exposed to short-term LT (4 C for 48 h), a 50% growth reduction accompanied by an increase in the content of superoxide, nitric oxide, and peroxynitrite, in addition to diminished cytosolic NADP-ME activity, were found. In vitro assays confirmed that peroxynitrite inhibits cytosolic NADP-ME2 activity due to tyrosine nitration. The mass spectrometric analysis of nitrated NADP-ME2 enabled us to determine that Tyr-73 was exclusively nitrated to 3-nitrotyrosine by peroxynitrite. The in silico analysis of the Arabidopsis NADP-ME2 protein sequence suggests that Tyr73 nitration could disrupt the interactions between the specific amino acids responsible for protein structure stability. In conclusion, the present data show that short-term LT stress a ects the metabolism of ROS and RNS, which appears to negatively modulate the activity of cytosolic NADP-ME through the tyrosine nitration process.engAtribución-SinDerivadas 3.0 Españahttp://creativecommons.org/licenses/by-nd/3.0/es/NADP malic enzymeLow temperatureNitric oxideTyrosine nitrationPeroxynitriteReactive oxygen speciesReactive nitrogen speciesNitro-oxidative stressinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/openAccess