Mechanism and importance of post-translational regulation of nitrate reductase

Lillo, Cathrine; Meyer, Christian; Lea, Unni S.; Provan, Fiona; Oltedal, Satu

doi:10.1093/jxb/erh132

Cited by 169 publications

(147 citation statements)

References 46 publications

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“…This peak during the light phase evidences a light-dependent activation/inactivation response as have been reported by Lillo et al (2004) for land plants.…”

Section: Light Darksupporting

confidence: 82%

“…In higher plants, light has been showed to induce NR activity in two ways, (1) rapid (minutes) induction, modulating the activation of pre-existing protein, and (2) slow (hours, days), inducing NR gene expression, in this case, the effect of the light could be replaced by glucose (Lillo et al 2004). Based on what is known for higher plants, glucose was added to the growing media to see its effect on NR activity.…”

Section: Light Darkmentioning

confidence: 99%

“…Regulatory mechanisms of the enzymatic activity include complex modulator processes to optimize nitrogen assimilation and prevent the formation of toxic products. The post-translational control of NR by phosphorylation is the most important controlling mechanism to avoid this deleterious accumulation (Lillo et al 2004), but there are many aspects still to be solved, opening an interesting research area to elucidate the signalling mechanism that modulates the nitrogen assimilatory pathway in macroalgae.…”

Section: Light Darkmentioning

confidence: 99%

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Characterization of nitrate reductase activity in vitro in Gracilaria caudata J. Agardh (Rhodophyta, Gracilariales)

et al. 2007

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-(Characterization of nitrate reductase activity in vitro in Gracilaria caudata J. Agardh (Rhodophyta, Gracilariales)). The marine red alga Gracilaria caudata J. Agardh has been used in Brazil for agar extraction, mainly in the northeast region of the country. Nitrogen availability is the most important abiotic factor in seawater that limits the growth of seaweeds. The enzyme nitrate reductase (NR) is the key regulatory point in the nitrogen assimilation in photosynthetic organisms. This study describes an in vitro assay, characterizing the enzymatic activity of NR in terms of kinetic constants and stability, its oscillation during the day and glucose effect on NR modulation. Maximal peaks of NR activity were recorded at 20 °C and pH 8.0. The enzymatic stability in crude extracts stored at 3 ± 1 °C decreased significantly after 48 hours. Apparent Michaelis-Menten constants (K M ) for NADH and nitrate were 22 µM and 3.95 mM, respectively. Gracilaria caudata NR activity showed an oscillation under light:dark photoperiod (14:10 hours LD) with 3-fold higher activity during the light phase, peaking after 10 hours of light. Under optimal assay conditions, the maximal activity was 92.9 10 -3 U g -1 . The addition of glucose induced the enzymatic activity during the light and dark phase, evidencing a possible modulation of this enzyme by the photosynthesis. This relationship can be explained by the need of carbon skeletons, produced by the photosynthetic process, to incorporate the intermediary metabolites of nitrate assimilatory pathway, avoiding the toxic intracellular accumulation of nitrite and ammonium. The optimization of enzymatic assay protocols for NR is essential to establish appropriate conditions to study nutritional behaviour, compare different taxonomic groups and to understand its regulatory mechanism.Key words -agarophyte, Gracilaria caudata, nitrate reductase, nitrogen metabolism RESUMO -(Caracterização da atividade in vitro da enzima nitrato redutase em Gracilaria caudata J. Agardh (Gracilariales, Rhodophyta)). A alga vermelha Gracilaria caudata J. Agardh tem sido utilizada no Brasil para a extração de ágar, principalmente no Nordeste do país. Na água do mar, a disponibilidade de nitrogênio é o principal fator abiótico que limita o crescimento de macroalgas. A enzima nitrato redutase (NR) é o ponto chave na regulação da assimilação do nitrogênio em organismos fotossintetizantes. Este estudo descreve o ensaio in vitro para caracterizar a atividade enzimática da NR em termos de constantes cinéticas e estabilidade, avalia sua oscilação ao longo do dia e a influência da glicose na modulação dessa enzima. Picos máximos de atividade da NR foram observados a 20 °C e pH 8,0. A estabilidade enzimática do extrato bruto armazenado a 3 ± 1 °C foi significativamente reduzida após 48 horas. As constantes aparentes de Michaelis-Menten (K M ) para NADH e nitrato foram 22 µM e 3,95 mM, respectivamente. A atividade da NR apresentou oscilação sob fotoperíodo de 14 horas de luz e10 horas de escuro com três vezes ...

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“…This peak during the light phase evidences a light-dependent activation/inactivation response as have been reported by Lillo et al (2004) for land plants.…”

Section: Light Darksupporting

confidence: 82%

Section: Light Darkmentioning

confidence: 99%

Section: Light Darkmentioning

confidence: 99%

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Characterization of nitrate reductase activity in vitro in Gracilaria caudata J. Agardh (Rhodophyta, Gracilariales)

et al. 2007

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“…By contrast, manipulating post-translational processes may have marked consequences on metabolic flux. For example in plants, abolition of the post-translational regulation of just one enzyme (a nitrate reductase) is sufficient to increase the corresponding flux of nitric oxide (35). In Bacillus subtilis, the phosphorylation state of one protein (Crh, a phosphocarrier protein) controls the flux through the methylglyoxal pathway, which is an alternative route of glycolysis in bacteria (36).…”

mentioning

confidence: 99%

Linking Post-Translational Modifications and Variation of Phenotypic Traits

Albertin

Marullo

Bely

et al. 2013

Molecular & Cellular Proteomics

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Enzymes can be post-translationally modified, leading to isoforms with different properties. The phenotypic consequences of the quantitative variability of isoforms have never been studied. We used quantitative proteomics to dissect the relationships between the abundances of the enzymes and isoforms of alcoholic fermentation, metabolic traits, and growth-related traits in Saccharomyces cerevisiae. Although the enzymatic pool allocated to the fermentation proteome was constant over the culture media and the strains considered, there was variation in abundance of individual enzymes and sometimes much more of their isoforms, which suggests the existence of selective constraints on total protein abundance and trade-offs between isoforms. Variations in abundance of some isoforms were significantly associated to metabolic traits and growth-related traits. In particular, cell size and maximum population size were highly correlated to the degree of N-terminal acetylation of the alcohol dehydrogenase. The fermentation proteome was found to be shaped by human selection, through the differential targeting of a few isoforms for each food-processing origin of strains. These results highlight the importance of posttranslational modifications in the diversity of metabolic and life-history traits. Molecular & Cellular Proteomics 12: 10.1074/mcp.M112.024349, 720 -735, 2013.The key problem in understanding genotype-phenotype relationships is the complexity arising from multiple levels of cellular functioning. Among them, metabolic networks involve series of interconnected chemical reactions catalyzed by enzymes, allowing the transformation of input substrates into intermediate or final metabolites. These networks play an essential role in an organism's growth, reproduction, and ability to maintain cell integrity and to respond to environmental changes (1, 2). The metabolic fluxes, as well as the metabolite concentrations, are governed by the activity of the enzymes, which depends on three types of factors: kinetic parameters, enzyme abundance, and activation state of the enzyme. The kinetic parameters are determined by the sequence and the three-dimensional structure of the protein (3). The abundance of the enzymes is the result of numerous molecular processes taking place from the transcriptional to the translational level, including epigenetic modifications of the DNA and chromatin (4), transcriptional regulation by transcription factors (5), mRNA capping and splicing and small RNA regulation (6), protein turnover (7), etc. The enzyme activation state is primarily because of post-translational modifications of the native protein, themselves highly regulated (8, 9). Other mechanisms involved in enzyme activity are proteinprotein interactions and allosteric regulation, such mechanisms being sometimes mediated through post-translational modifications (10, 11). The resulting isoforms can display differences in activity, affinity for partners (protein or effectors), and stability (12). The most studied modification is the reversibl...

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“…1B). In plants the hinge 1 region, which connects the Moco and heme domain, was shown to be important for NR activity regulation (6), and likewise the N-terminal extension is thought to possibly have a function in the post-transcriptional regulation of NR activity (7).…”

mentioning

confidence: 99%

Biochemical Characterization of Molybdenum Cofactor-free Nitrate Reductase from Neurospora crassa

Ringel

Krausze

Heuvel

et al. 2013

Journal of Biological Chemistry

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Background: Eukaryotic nitrate reductase maturation is poorly understood. Results: Binding of molybdenum cofactor to apo-nitrate reductase is independent from other prosthetic groups. Conclusion: Active site formation of eukaryotic nitrate reductase is an autonomous process intrinsically tied to nitrate reductase dimerization. Significance: The understanding of molybdenum cofactor-dependent enzyme maturation is of significance as molybdenum enzymes are involved in essential cellular processes.

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Mechanism and importance of post-translational regulation of nitrate reductase

Cited by 169 publications

References 46 publications

Characterization of nitrate reductase activity in vitro in Gracilaria caudata J. Agardh (Rhodophyta, Gracilariales)

Characterization of nitrate reductase activity in vitro in Gracilaria caudata J. Agardh (Rhodophyta, Gracilariales)

Linking Post-Translational Modifications and Variation of Phenotypic Traits

Biochemical Characterization of Molybdenum Cofactor-free Nitrate Reductase from Neurospora crassa

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