Artículos de revistas: "Prolin catabolism"

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Guerrier, Gilles. "Effect of salt-stress on proline metabolism in calli of Lycopersicon esculentum, Lycopersicon pennellii, and their interspecific hybrid". Canadian Journal of Botany 73, n.º 12 (1 de diciembre de 1995): 1939–46. http://dx.doi.org/10.1139/b95-206.

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Amino acid pools and enzyme activities of NH3-assimilation (glutamine synthetase, glutamate synthase), proline biosynthesis (pyrroline-5-carboxylate reductase), proline catabolism (proline dehydrogenase, proline oxidase), and ornithine transamination (ornithine transaminase) were determined in control and salinized (140 mM NaCl) calli from tomato roots. Three populations were used: the domestic salt-sensitive Lycopersicon esculentum Mill. cv. P-73, the wild salt-tolerant Lycopersicon pennellii (Correll) D'Arcy, accession PE-47, and their F1 interspecific cross, for which the relative growth rate on salt media was intermediate to those of the parents. Compared with control conditions, proline levels increased with NaCl treatments by twofold, threefold, and sixfold in the wild species, the F1 hybrid, and the domestic species, respectively. This proline accumulation in the F1 and the domestic populations was not modulated by changes in the enzyme activities of proline biosynthesis or catabolism. NaCl tolerance, amino acid (proline, alanine, arginine, asparagine) content, and velocity of enzymes responsible for proline biosynthesis and catabolism are dependent on explant sources (cotyledon, root) from which the F1 calli were derived. The comparison of proline (PRO) responses in the different calli and populations indicated (i) various changes in anabolic or catabolic rates of PRO metabolism for a given range of PRO accumulation and (ii) the presence in the F1 of both wild and sensitive parent characters in growth and PRO responses. Key words: callus culture, Lycopersicon esculentum, Lycopersicon pennellii, F1 tomato, proline synthesis, proline catabolism, salt stress.

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Grantham, Barbara D. y J. Barrett. "Amino acid catabolism in the nematodes Heligmosomoides polygyrus and Panagrellus redivivus 2. Metabolism of the carbon skeleton". Parasitology 93, n.º 3 (diciembre de 1986): 495–504. http://dx.doi.org/10.1017/s0031182000081208.

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SUMMARYAll of the enzymes of proline catabolism were present in Heligmosomoides polygyrus and Panagrellus redivivus and the activities were, in general, similar to those found in rat liver. Both nematodes were also shown to be able to catabolize the branched-chain amino acids leucine, isoleucine and valine, by pathways similar to those found in mammalian liver. There were no significant differences in amino acid catabolism between the animal-parasitic and free-living species of nematode.

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Phillips, Donald A., Eve S. Sande, J. A. C. Vriezen, Frans J. de Bruijn, Daniel Le Rudulier y Cecillia M. Joseph. "A New Genetic Locus in Sinorhizobium meliloti Is Involved in Stachydrine Utilization". Applied and Environmental Microbiology 64, n.º 10 (1 de octubre de 1998): 3954–60. http://dx.doi.org/10.1128/aem.64.10.3954-3960.1998.

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ABSTRACT Stachydrine, a betaine released by germinating alfalfa seeds, functions as an inducer of nodulation genes, a catabolite, and an osmoprotectant in Sinorhizobium meliloti. Two stachydrine-inducible genes were found in S. meliloti1021 by mutation with a Tn5-luxAB promoter probe. Both mutant strains (S10 and S11) formed effective alfalfa root nodules, but neither grew on stachydrine as the sole carbon and nitrogen source. When grown in the absence or presence of salt stress, S10 and S11 took up [14C]stachydrine as well as wild-type cells did, but neither used stachydrine effectively as an osmoprotectant. In the absence of salt stress, both S10 and S11 took up less [14C]proline than wild-type cells did. S10 and S11 appeared to colonize alfalfa roots normally in single-strain tests, but when mixed with the wild-type strain, their rhizosphere counts were reduced more than 50% (P ≤ 0.01) relative to the wild type. These results suggest that stachydrine catabolism contributes to root colonization. DNA sequence analysis identified the mutated locus in S11 as putA, and the luxABfusion in that gene was induced by proline as well as stachydrine. DNA that restored the capacity of mutant S10 to catabolize stachydrine contained a new open reading frame, stcD. All data are consistent with the concept that stcD codes for an enzyme that produces proline by demethylation of N-methylproline, a degradation product of stachydrine.

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Diab, Farès, Théophile Bernard, Alexis Bazire, Dominique Haras, Carlos Blanco y Mohamed Jebbar. "Succinate-mediated catabolite repression control on the production of glycine betaine catabolic enzymes in Pseudomonas aeruginosa PAO1 under low and elevated salinities". Microbiology 152, n.º 5 (1 de mayo de 2006): 1395–406. http://dx.doi.org/10.1099/mic.0.28652-0.

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Glycine betaine (GB) and its immediate precursors choline and carnitine, dimethylsulfonioacetate, dimethylsulfoniopropionate, ectoine and proline were effective osmoprotectants for Pseudomonas aeruginosa, but pipecolate, trehalose and sucrose had no osmoprotective effect. GB was accumulated stably or transiently when succinate or glucose, respectively, was used as a carbon and energy source. The catabolite repression mediated by succinate occurred at both low and high salinities, and it did not involve the global regulators Vfr and Crc. A proteomic analysis showed that at least 21 proteins were induced when GB was used as a carbon and energy source, and provided evidence that succinate repressed the synthesis of all these proteins. Many of the proteins induced by GB (sarcosine oxidase, serine hydroxymethyltransferase and serine dehydratase) are involved in GB catabolism. In addition, GB uptake was stimulated at high medium osmolalities but it was insensitive to catabolite repression by succinate. Despite its ability to inhibit betaine catabolism, succinate did not allow any better growth of P. aeruginosa cells under hyperosmotic constraint. Conversely, as observed for cells supplied with glucose, a transient accumulation of GB was sufficient to provide a significant cell osmoprotection.

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5

Tanner, John J. "Structural biology of proline catabolism". Amino Acids 35, n.º 4 (28 de marzo de 2008): 719–30. http://dx.doi.org/10.1007/s00726-008-0062-5.

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Deutch, Charles E., James M. Hasler, Rochelle M. Houston, Manish Sharma y Valerie J. Stone. "Nonspecific inhibition of proline dehydrogenase synthesis in Escherichia coli during osmotic stress". Canadian Journal of Microbiology 35, n.º 8 (1 de agosto de 1989): 779–85. http://dx.doi.org/10.1139/m89-130.

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L-Proline, which is accumulated by Escherichia coli during growth in media of high osmolality, also induces the synthesis of the enzyme degrading it to glutamate. To determine if proline catabolism is inhibited during osmotic stress, proline utilization and the formation of proline dehydrogenase were examined in varying concentrations of NaCl and sucrose. Although the specific growth rate of E. coli with proline as the sole nitrogen source diminished as the solute osmolality increased, a comparable reduction in growth rate occurred with ammonium as the primary nitrogen source. Proline catabolism, as measured in whole cells by the conversion of [14C]proline to [14C]glutamate, was only slightly inhibited by solute osmolalities up to 1.0 osmol/kg; more than 50% of the initial activity was still found at 2.0 osmol/kg. By contrast, the specific activity of proline dehydrogenase in bacteria grown in the presence of added solutes decreased to less than 20% of the control level. This reduction was related to a lower rate of synthesis, but was independent of genes currently known to be involved in osmoregulation or proline metabolism. The specific activities of tryptophanase, β-galactosidase, and histidinol dehydrogenase were also reduced under similar growth conditions. These results indicate that while proline catabolism is not directly inhibited by high solute concentrations, prolonged exposure to osmotic stress leads to its reduction as part of a more general metabolic response.Key words: osmotic stress, proline, proline catabolism, proline dehydrogenase, PutA protein.

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7

Pallag, Gergely, Sara Nazarian, Dora Ravasz, David Bui, Timea Komlódi, Carolina Doerrier, Erich Gnaiger, Thomas N. Seyfried y Christos Chinopoulos. "Proline Oxidation Supports Mitochondrial ATP Production When Complex I Is Inhibited". International Journal of Molecular Sciences 23, n.º 9 (4 de mayo de 2022): 5111. http://dx.doi.org/10.3390/ijms23095111.

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The oxidation of proline to pyrroline-5-carboxylate (P5C) leads to the transfer of electrons to ubiquinone in mitochondria that express proline dehydrogenase (ProDH). This electron transfer supports Complexes CIII and CIV, thus generating the protonmotive force. Further catabolism of P5C forms glutamate, which fuels the citric acid cycle that yields the reducing equivalents that sustain oxidative phosphorylation. However, P5C and glutamate catabolism depend on CI activity due to NAD+ requirements. NextGen-O2k (Oroboros Instruments) was used to measure proline oxidation in isolated mitochondria of various mouse tissues. Simultaneous measurements of oxygen consumption, membrane potential, NADH, and the ubiquinone redox state were correlated to ProDH activity and F1FO-ATPase directionality. Proline catabolism generated a sufficiently high membrane potential that was able to maintain the F1FO-ATPase operation in the forward mode. This was observed in CI-inhibited mouse liver and kidney mitochondria that exhibited high levels of proline oxidation and ProDH activity. This action was not observed under anoxia or when either CIII or CIV were inhibited. The duroquinone fueling of CIII and CIV partially reproduced the effects of proline. Excess glutamate, however, could not reproduce the proline effect, suggesting that processes upstream of the glutamate conversion from proline were involved. The ProDH inhibitors tetrahydro-2-furoic acid and, to a lesser extent, S-5-oxo-2-tetrahydrofurancarboxylic acid abolished all proline effects. The data show that ProDH-directed proline catabolism could generate sufficient CIII and CIV proton pumping, thus supporting ATP production by the F1FO-ATPase even under CI inhibition.

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Belitsky, Boris R. y Abraham L. Sonenshein. "Modulation of Activity of Bacillus subtilis Regulatory Proteins GltC and TnrA by Glutamate Dehydrogenase". Journal of Bacteriology 186, n.º 11 (1 de junio de 2004): 3399–407. http://dx.doi.org/10.1128/jb.186.11.3399-3407.2004.

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ABSTRACT The Bacillus subtilis gltAB operon, encoding glutamate synthase, requires a specific positive regulator, GltC, for its expression and is repressed by the global regulatory protein TnrA. The factor that controls TnrA activity, a complex of glutamine synthetase and a feedback inhibitor, such as glutamine, is known, but the signal for modulation of GltC activity has remained elusive. GltC-dependent gltAB expression was drastically reduced when cells were grown in media containing arginine or ornithine or proline, all of which are inducers and substrates of the Roc catabolic pathway. Analysis of gltAB expression in mutants with various defects in the Roc pathway indicated that rocG-encoded glutamate dehydrogenase was required for such repression, suggesting that the substrates or products of this enzyme are the real effectors of GltC. Given that RocG is an enzyme of glutamate catabolism, the main regulatory role of GltC may be prevention of a futile cycle of glutamate synthesis and degradation in the presence of arginine-related amino acids or proline. In addition, high activity of glutamate dehydrogenase was incompatible with activity of TnrA.

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9

Cruz-Leite, Vanessa Rafaela Milhomem, André Luís Elias Moreira, Lana O’Hara Souza Silva, Moises Morais Inácio, Juliana Alves Parente-Rocha, Orville Hernandez Ruiz, Simone Schneider Weber, Célia Maria de Almeida Soares y Clayton Luiz Borges. "Proteomics of Paracoccidioides lutzii: Overview of Changes Triggered by Nitrogen Catabolite Repression". Journal of Fungi 9, n.º 11 (12 de noviembre de 2023): 1102. http://dx.doi.org/10.3390/jof9111102.

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Members of the Paracoccidioides complex are the causative agents of Paracoccidioidomycosis (PCM), a human systemic mycosis endemic in Latin America. Upon initial contact with the host, the pathogen needs to uptake micronutrients. Nitrogen is an essential source for biosynthetic pathways. Adaptation to nutritional stress is a key feature of fungi in host tissues. Fungi utilize nitrogen sources through Nitrogen Catabolite Repression (NCR). NCR ensures the scavenging, uptake and catabolism of alternative nitrogen sources, when preferential ones, such as glutamine or ammonium, are unavailable. The NanoUPLC-MSE proteomic approach was used to investigate the NCR response of Paracoccidioides lutzii after growth on proline or glutamine as a nitrogen source. A total of 338 differentially expressed proteins were identified. P. lutzii demonstrated that gluconeogenesis, β-oxidation, glyoxylate cycle, adhesin-like proteins, stress response and cell wall remodeling were triggered in NCR-proline conditions. In addition, within macrophages, yeast cells trained under NCR-proline conditions showed an increased ability to survive. In general, this study allows a comprehensive understanding of the NCR response employed by the fungus to overcome nutritional starvation, which in the human host is represented by nutritional immunity. In turn, the pathogen requires rapid adaptation to the changing microenvironment induced by macrophages to achieve successful infection.

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10

Chen, Siyun, Catharine E. White, George C. diCenzo, Ye Zhang, Peter J. Stogios, Alexei Savchenko y Turlough M. Finan. "l-Hydroxyproline and d-Proline Catabolism in Sinorhizobium meliloti". Journal of Bacteriology 198, n.º 7 (1 de febrero de 2016): 1171–81. http://dx.doi.org/10.1128/jb.00961-15.

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ABSTRACTSinorhizobium melilotiforms N2-fixing root nodules on alfalfa, and as a free-living bacterium, it can grow on a very broad range of substrates, includingl-proline and several related compounds, such as proline betaine,trans-4-hydroxy-l-proline (trans-4-l-Hyp), andcis-4-hydroxy-d-proline (cis-4-d-Hyp). Fourteenhypgenes are induced upon growth ofS. melilotiontrans-4-l-Hyp, and of those,hypMNPQencodes an ABC-typetrans-4-l-Hyp transporter andhypREencodes an epimerase that convertstrans-4-l-Hyp tocis-4-d-Hyp in the bacterial cytoplasm. Here, we present evidence that the HypO, HypD, and HypH proteins catalyze the remaining steps in whichcis-4-d-Hyp is converted to α-ketoglutarate. The HypO protein functions as ad-amino acid dehydrogenase, convertingcis-4-d-Hyp to Δ1-pyrroline-4-hydroxy-2-carboxylate, which is deaminated by HypD to α-ketoglutarate semialdehyde and then converted to α-ketoglutarate by HypH. The crystal structure of HypD revealed it to be a member of theN-acetylneuraminate lyase subfamily of the (α/β)8protein family and is consistent with the known enzymatic mechanism for other members of the group. It was also shown thatS. melilotican catabolized-proline as both a carbon and a nitrogen source, thatd-proline can complementl-proline auxotrophy, and that the catabolism ofd-proline is dependent on thehypcluster. Transport ofd-proline involves the HypMNPQ transporter, following whichd-proline is converted to Δ1-pyrroline-2-carboxylate (P2C) largely via HypO. The P2C is converted tol-proline through the NADPH-dependent reduction of P2C by the previously uncharacterized HypS protein. Thus, overall, we have now completed detailed genetic and/or biochemical characterization of 9 of the 14hypgenes.IMPORTANCEHydroxyproline is abundant in proteins in animal and plant tissues and serves as a carbon and a nitrogen source for bacteria in diverse environments, including the rhizosphere, compost, and the mammalian gut. While the main biochemical features of bacterial hydroxyproline catabolism were elucidated in the 1960s, the genetic and molecular details have only recently been determined. Elucidating the genetics of hydroxyproline catabolism will aid in the annotation of these genes in other genomes and metagenomic libraries. This will facilitate an improved understanding of the importance of this pathway and may assist in determining the prevalence of hydroxyproline in a particular environment.

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11

Boncompagni, Eric, Laurence Dupont, Tam Mignot, Magne Østeräs, Annie Lambert, Marie-Christine Poggi y Daniel Le Rudulier. "Characterization of a Sinorhizobium melilotiATP-Binding Cassette Histidine Transporter Also Involved in Betaine and Proline Uptake". Journal of Bacteriology 182, n.º 13 (1 de julio de 2000): 3717–25. http://dx.doi.org/10.1128/jb.182.13.3717-3725.2000.

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ABSTRACT The symbiotic soil bacterium Sinorhizobium melilotiuses the compatible solutes glycine betaine and proline betaine for both protection against osmotic stress and, at low osmolarities, as an energy source. A PCR strategy based on conserved domains in components of the glycine betaine uptake systems from Escherichia coli(ProU) and Bacillus subtilis (OpuA and OpuC) allowed us to identify a highly homologous ATP-binding cassette (ABC) binding protein-dependent transporter in S. meliloti. This system was encoded by three genes (hutXWV) of an operon which also contained a fourth gene (hutH2) encoding a putative histidase, which is an enzyme involved in the first step of histidine catabolism. Site-directed mutagenesis of the gene encoding the periplasmic binding protein (hutX) and of the gene encoding the cytoplasmic ATPase (hutV) was done to study the substrate specificity of this transporter and its contribution in betaine uptake. These mutants showed a 50% reduction in high-affinity uptake of histidine, proline, and proline betaine and about a 30% reduction in low-affinity glycine betaine transport. When histidine was used as a nitrogen source, a 30% inhibition of growth was observed inhut mutants (hutX and hutH2). Expression analysis of the hut operon determined using ahutX-lacZ fusion revealed induction by histidine, but not by salt stress, suggesting this uptake system has a catabolic role rather than being involved in osmoprotection. To our knowledge, Hut is the first characterized histidine ABC transporter also involved in proline and betaine uptake.

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12

Belostotsky, Ruth y Yaacov Frishberg. "Catabolism of Hydroxyproline in Vertebrates: Physiology, Evolution, Genetic Diseases and New siRNA Approach for Treatment". International Journal of Molecular Sciences 23, n.º 2 (17 de enero de 2022): 1005. http://dx.doi.org/10.3390/ijms23021005.

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Hydroxyproline is one of the most prevalent amino acids in animal proteins. It is not a genetically encoded amino acid, but, rather, it is produced by the post-translational modification of proline in collagen, and a few other proteins, by prolyl hydroxylase enzymes. Although this post-translational modification occurs in a limited number of proteins, its biological significance cannot be overestimated. Considering that hydroxyproline cannot be re-incorporated into pro-collagen during translation, it should be catabolized following protein degradation. A cascade of reactions leads to production of two deleterious intermediates: glyoxylate and hydrogen peroxide, which need to be immediately converted. As a result, the enzymes involved in hydroxyproline catabolism are located in specific compartments: mitochondria and peroxisomes. The particular distribution of catabolic enzymes in these compartments, in different species, depends on their dietary habits. Disturbances in hydroxyproline catabolism, due to genetic aberrations, may lead to a severe disease (primary hyperoxaluria), which often impairs kidney function. The basis of this condition is accumulation of glyoxylate and its conversion to oxalate. Since calcium oxalate is insoluble, children with this rare inherited disorder suffer from progressive kidney damage. This condition has been nearly incurable until recently, as significant advances in substrate reduction therapy using small interference RNA led to a breakthrough in primary hyperoxaluria type 1 treatment.

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13

Kijowska-Oberc, Joanna, Mikołaj K. Wawrzyniak, Liliana Ciszewska y Ewelina Ratajczak. "Evaluation of P5CS and ProDH activity in Paulownia tomentosa (Steud.) as an indicator of oxidative changes induced by drought stress". PeerJ 12 (25 de enero de 2024): e16697. http://dx.doi.org/10.7717/peerj.16697.

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The aim of the study was to investigate changes in proline metabolism in seedlings of tree species during drought stress. One month old Paulownia tomentosa seedlings were exposed to moisture conditions at various levels (irrigation at 100, 75, 50 and 25% of field capacity), and then the material (leaves and roots) was collected three times at 10-day intervals. The activity of enzymes involved in proline metabolism was closely related to drought severity; however, proline content was not directly impacted. The activity of pyrroline-5-carboxylate synthetase (P5CS), which catalyzes proline biosynthesis, increased in response to hydrogen peroxide accumulation, which was correlated with soil moisture. In contrast, the activity of proline dehydrogenase (ProDH), which catalyzes proline catabolism, decreased. Compared to proline, the activity of these enzymes may be a more reliable biochemical marker of stress-induced oxidative changes. The content of proline is dependent on numerous additional factors, i.e., its degradation is an important alternative energy source. Moreover, we noted tissue-specific differences in this species, in which roots appeared to be proline biosynthesis sites and leaves appeared to be proline catabolism sites. Further research is needed to examine a broader view of proline metabolism as a cycle regulated by multiple mechanisms and differences between species.

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14

Silao, Fitz Gerald S., Tong Jiang, Biborka Bereczky-Veress, Andreas Kühbacher, Kicki Ryman, Nathalie Uwamohoro, Sabrina Jenull et al. "Proline catabolism is a key factor facilitating Candida albicans pathogenicity". PLOS Pathogens 19, n.º 11 (2 de noviembre de 2023): e1011677. http://dx.doi.org/10.1371/journal.ppat.1011677.

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Candida albicans, the primary etiology of human mycoses, is well-adapted to catabolize proline to obtain energy to initiate morphological switching (yeast to hyphal) and for growth. We report that put1-/- and put2-/- strains, carrying defective Proline UTilization genes, display remarkable proline sensitivity with put2-/- mutants being hypersensitive due to the accumulation of the toxic intermediate pyrroline-5-carboxylate (P5C), which inhibits mitochondrial respiration. The put1-/- and put2-/- mutations attenuate virulence in Drosophila and murine candidemia models and decrease survival in human neutrophils and whole blood. Using intravital 2-photon microscopy and label-free non-linear imaging, we visualized the initial stages of C. albicans cells infecting a kidney in real-time, directly deep in the tissue of a living mouse, and observed morphological switching of wildtype but not of put2-/- cells. Multiple members of the Candida species complex, including C. auris, are capable of using proline as a sole energy source. Our results indicate that a tailored proline metabolic network tuned to the mammalian host environment is a key feature of opportunistic fungal pathogens.

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Dellero, Younes, Vanessa Clouet, Nathalie Marnet, Anthoni Pellizzaro, Sylvain Dechaumet, Marie-Françoise Niogret y Alain Bouchereau. "Leaf status and environmental signals jointly regulate proline metabolism in winter oilseed rape". Journal of Experimental Botany 71, n.º 6 (6 de diciembre de 2019): 2098–111. http://dx.doi.org/10.1093/jxb/erz538.

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Abstract Proline metabolism is an essential component of plant adaptation to multiple environmental stress conditions that is also known to participate in specific developmental phases, particularly in reproductive organs. Recent evidence suggested a possible role for proline catabolism in Brassica napus for nitrogen remobilization processes from source leaves at the vegetative stage. Here, we investigate transcript levels of Δ1-PYRROLINE-5-CARBOXYLATE SYNTHASE (P5CS) and PROLINE DEHYDROGENASE (ProDH) genes at the vegetative stage with respect to net proline biosynthesis and degradation fluxes in leaves having a different sink/source balance. We showed that the underexpression of three P5CS1 genes in source leaves was accompanied by a reduced commitment of de novo assimilated 15N towards proline biosynthesis and an overall depletion of free proline content. We found that the expression of ProDH genes was strongly induced by carbon starvation conditions (dark-induced senescence) compared with early senescing leaves. Our results suggested a role for proline catabolism in B. napus, but acting only at a late stage of senescence. In addition, we also identified some P5CS and ProDH genes that were differentially expressed during multiple processes (leaf status, dark to light transition, and stress response).

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Salmon, Jean-Michel y Pierre Barre. "Improvement of Nitrogen Assimilation and Fermentation Kinetics under Enological Conditions by Derepression of Alternative Nitrogen-Assimilatory Pathways in an Industrial Saccharomyces cerevisiae Strain". Applied and Environmental Microbiology 64, n.º 10 (1 de octubre de 1998): 3831–37. http://dx.doi.org/10.1128/aem.64.10.3831-3837.1998.

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ABSTRACT Metabolism of nitrogen compounds by yeasts affects the efficiency of wine fermentation. Ammonium ions, normally present in grape musts, reduce catabolic enzyme levels and transport activities for nonpreferred nitrogen sources. This nitrogen catabolite repression severely impairs the utilization of proline and arginine, both common nitrogen sources in grape juice that require the proline utilization pathway for their assimilation. We attempted to improve fermentation performance by genetic alteration of the regulation of nitrogen-assimilatory pathways in Saccharomyces cerevisiae. One mutant carrying a recessive allele ofure2 was isolated from an industrial S. cerevisiae strain. This mutation strongly deregulated the proline utilization pathway. Fermentation kinetics of this mutant were studied under enological conditions on simulated standard grape juices with various nitrogen levels. Mutant strains produced more biomass and exhibited a higher maximum CO2 production rate than the wild type. These differences were primarily due to the derepression of amino acid utilization pathways. When low amounts of dissolved oxygen were added, the mutants could assimilate proline. Biomass yield and fermentation rate were consequently increased, and the duration of the fermentation was substantially shortened. S. cerevisiae strains lacking URE2 function could improve alcoholic fermentation of natural media where proline and other poorly assimilated amino acids are the major potential nitrogen source, as is the case for most fruit juices and grape musts.

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Moses, S., T. Sinner, A. Zaprasis, N. Stoveken, T. Hoffmann, B. R. Belitsky, A. L. Sonenshein y E. Bremer. "Proline Utilization by Bacillus subtilis: Uptake and Catabolism". Journal of Bacteriology 194, n.º 4 (2 de diciembre de 2011): 745–58. http://dx.doi.org/10.1128/jb.06380-11.

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Tang, Haiqing y Shanshan Pang. "Proline Catabolism Modulates Innate Immunity in Caenorhabditis elegans". Cell Reports 17, n.º 11 (diciembre de 2016): 2837–44. http://dx.doi.org/10.1016/j.celrep.2016.11.038.

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Deutch, Charles E. "l-Proline nutrition and catabolism in Staphylococcus saprophyticus". Antonie van Leeuwenhoek 99, n.º 4 (21 de enero de 2011): 781–93. http://dx.doi.org/10.1007/s10482-011-9552-7.

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Petersen, J. G., M. C. Kielland-Brandt, T. Nilsson-Tillgren, C. Bornaes y S. Holmberg. "Molecular genetics of serine and threonine catabolism in Saccharomyces cerevisiae." Genetics 119, n.º 3 (1 de julio de 1988): 527–34. http://dx.doi.org/10.1093/genetics/119.3.527.

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Abstract The catabolic L-serine (L-threonine) deaminase of Saccharomyces cerevisiae allows the yeast to grow on media with L-serine or L-threonine as sole nitrogen source. A mutant, cha1 (catabolism of hydroxyamino acids), lacking this enzyme activity has been isolated. We have cloned the CHA1 gene by complementation of a cha1 mutation. Northern analysis showed that CHA1 mRNA has a size of about 1200 ribonucleotides. CHA1 is probably the structural gene for the enzyme; it is an abundant RNA in cells grown with serine and threonine as nitrogen source, whereas it is not detected when cells are grown on ammonium or proline, i.e., the transcription of the CHA1 gene is induced by serine or threonine. Under induced growth conditions haploid ilv1 CHA1 strains do not require isoleucine, i.e., the catabolic deaminase is able to substitute for the biosynthetic threnonine deaminase encoded by the ILV1 gene. We have identified a nuclear, recessive mutation, sil1, that suppresses ilv1 mutations by increased transcription of the CHA1 gene under growth conditions leading to partial induction. The sil1 mutation could exert its effect by increasing the effective pools of the hydroxyamino acids. Alternatively SIL1 may encode a negatively acting regulatory protein for CHA1.

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Vı́lchez, Susana, Maximino Manzanera y Juan L. Ramos. "Control of Expression of DivergentPseudomonas putida put Promoters for Proline Catabolism". Applied and Environmental Microbiology 66, n.º 12 (1 de diciembre de 2000): 5221–25. http://dx.doi.org/10.1128/aem.66.12.5221-5225.2000.

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ABSTRACT Pseudomonas putida KT2440 uses proline as the sole C and N source. Utilization of this amino acid involves its uptake, which is mediated by the PutP protein, and its conversion into glutamate, mediated by the PutA protein. Sequence analysis revealed that theputA and putP genes are transcribed divergently. Expression from the putP and putAgenes was analyzed at the mRNA level in different host backgrounds in the absence and presence of proline. Expression from theput promoters was induced by proline. The transcription initiation points of the putP and putA genes were precisely mapped via primer extension, and sequence analysis of the upstream DNA region showed well-separated promoters for these two genes. The PutA protein acts as a repressor of put gene expression in P. putida because expression from theput promoters is constitutive in a host background with a knockout putA gene. This regulatory activity is independent of the catabolic activity of PutA, because we show that a point mutation (Glu896→Lys) that prevents catalytic activity allowed the protein to retain its regulatory activity. Expression from theput promoters in the presence of proline in aputA-proficient background requires a positive regulatory protein, still unidentified, whose expression seems to be ς54 dependent because the put genes were not expressed in a ς54-deficient background. Expression of the putA and putP genes was equally high in the presence of proline in ς38- and ihf-deficientP. putida backgrounds.

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22

Edskes, Herman K., John A. Hanover y Reed B. Wickner. "Mks1p Is a Regulator of Nitrogen Catabolism Upstream of Ure2p in Saccharomyces cerevisiae". Genetics 153, n.º 2 (1 de octubre de 1999): 585–94. http://dx.doi.org/10.1093/genetics/153.2.585.

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Abstract The supply of nitrogen regulates yeast genes affecting nitrogen catabolism, pseudohyphal growth, and meiotic sporulation. Ure2p of Saccharomyces cerevisiae is a negative regulator of nitrogen catabolism that inhibits Gln3p, a positive regulator of DAL5, and other genes of nitrogen assimilation. Dal5p, the allantoate permease, allows ureidosuccinate uptake (Usa+) when cells grow on a poor nitrogen source such as proline. We find that overproduction of Mks1p allows uptake of ureidosuccinate on ammonia and lack of Mks1p prevents uptake of ureidosuccinate or Dal5p expression on proline. Overexpression of Mks1p does not affect cellular levels of Ure2p. An mks1 ure2 double mutant can take up ureidosuccinate on either ammonia or proline. Moreover, overexpression of Ure2p suppresses the ability of Mks1p overexpression to allow ureidosuccinate uptake on ammonia. These results suggest that Mks1p is involved in nitrogen control upstream of Ure2p as follows: NH3 2ADE; Mks1p 2ADE; Ure2p 2ADE; Gln3p → DAL5. Either overproduction of Mks1p or deletion of MKS1 interferes with pseudohyphal growth.

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23

Tanner, John J. "Structural Biology of Proline Catabolic Enzymes". Antioxidants & Redox Signaling 30, n.º 4 (febrero de 2019): 650–73. http://dx.doi.org/10.1089/ars.2017.7374.

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24

Lee, Haehee y Sangkee Rhee. "Structural and mutational analyses of the bifunctional arginine dihydrolase and ornithine cyclodeaminase AgrE from the cyanobacterium Anabaena". Journal of Biological Chemistry 295, n.º 17 (20 de marzo de 2020): 5751–60. http://dx.doi.org/10.1074/jbc.ra120.012768.

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In cyanobacteria, metabolic pathways that use the nitrogen-rich amino acid arginine play a pivotal role in nitrogen storage and mobilization. The N-terminal domains of two recently identified bacterial enzymes: ArgZ from Synechocystis and AgrE from Anabaena, have been found to contain an arginine dihydrolase. This enzyme provides catabolic activity that converts arginine to ornithine, resulting in concomitant release of CO2 and ammonia. In Synechocystis, the ArgZ-mediated ornithine–ammonia cycle plays a central role in nitrogen storage and remobilization. The C-terminal domain of AgrE contains an ornithine cyclodeaminase responsible for the formation of proline from ornithine and ammonia production, indicating that AgrE is a bifunctional enzyme catalyzing two sequential reactions in arginine catabolism. Here, the crystal structures of AgrE in three different ligation states revealed that it has a tetrameric conformation, possesses a binding site for the arginine dihydrolase substrate l-arginine and product l-ornithine, and contains a binding site for the coenzyme NAD(H) required for ornithine cyclodeaminase activity. Structure–function analyses indicated that the structure and catalytic mechanism of arginine dihydrolase in AgrE are highly homologous with those of a known bacterial arginine hydrolase. We found that in addition to other active-site residues, Asn-71 is essential for AgrE's dihydrolase activity. Further analysis suggested the presence of a passage for substrate channeling between the two distinct AgrE active sites, which are situated ∼45 Å apart. These results provide structural and functional insights into the bifunctional arginine dihydrolase–ornithine cyclodeaminase enzyme AgrE required for arginine catabolism in Anabaena.

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25

Culham, Doreen E., Katherine S. Emmerson, Bonnie Lasby, Daniel Mamelak, Brian A. Steer, Carlton L. Gyles, Merna Villarejo y Janet M. Wood. "Genes encoding osmoregulatory proline/glycine betaine transporters and the proline catabolic system are present and expressed in diverse clinical Escherichia coli isolates". Canadian Journal of Microbiology 40, n.º 5 (1 de mayo de 1994): 397–402. http://dx.doi.org/10.1139/m94-065.

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Sixty-three clinical isolates identified as Escherichia coli, 30 from the human urinary tract and 33 derived from other human origins, were screened for proline/glycine betaine transporters similar to those that support proline catabolism and proline- or glycine betaine-based osmoregulation in E. coli K-12. Both molecular (DNA- and protein-based) analyses and physiological tests were performed. All tests were calibrated with E. coli K-12 derivatives from which genetic loci putP (encoding a proline transporter required for proline catabolism), proP, and (or) proU (loci encoding osmoregulatory proline/glycine betaine transporters) had been deleted. All clinical isolates showed both enhanced sensitivity to the toxic proline analogue azetidine-2-carboxylate on media of high osmolality and growth stimulation by glycine betaine in an artificial urine preparation of high osmolality. DNA sequences similar to the putP, proP, and proU loci of E. coli K-12 were detected by DNA amplification and (or) hybridization and protein specifically reactive with antibodies raised against the ProX protein of E. coli K-12 (a ProU constituent) was detected by western blotting in over 95% of the isolates. Two anomalous isolates were reclassified as non-E. coli on the basis of the API 20E series of tests. A protein immunochemically cross-reactive with the ProP protein of E. coli K-12 was also expressed by the clinical isolates. Since all three transporters were ubiquitous, no particular correlation between clinical origin and PutP, ProP, or ProU activity was observed. These data suggest that the transporters encoded in loci putP, proP, and proU perform housekeeping functions essential for the survival of E. coli cells in diverse habitats.Key words: osmoregulation, betaine transport, urinary tract infection, Escherichia coli.

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26

Glenn, A. R., S. Holliday y M. J. Dilworth. "The transport and catabolism of l-proline by cowpeaRhizobiumNGR 234". FEMS Microbiology Letters 82, n.º 3 (agosto de 1991): 307–12. http://dx.doi.org/10.1111/j.1574-6968.1991.tb04900.x.

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27

Obungu, Victor H., Job K. Kiaira, R. Muturi Njogu y Norah K. Olembo. "Catabolism of proline by procyclic culture forms of Trypanosoma congolense". Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 123, n.º 1 (mayo de 1999): 59–65. http://dx.doi.org/10.1016/s0305-0491(99)00040-1.

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28

Casalino, Laura, Stefania Comes, Giuseppina Lambazzi, Benedetta De Stefano, Stefania Filosa, Sandro De Falco, Dario De Cesare, Gabriella Minchiotti y Eduardo Jorge Patriarca. "Control of embryonic stem cell metastability by l-proline catabolism". Journal of Molecular Cell Biology 3, n.º 2 (8 de febrero de 2011): 108–22. http://dx.doi.org/10.1093/jmcb/mjr001.

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29

Ayliffe, Michael A., Heidi J. Mitchell, Karen Deuschle y Anthony J. Pryor. "Comparative analysis in cereals of a key proline catabolism gene." Molecular Genetics and Genomics 274, n.º 5 (23 de septiembre de 2005): 494–505. http://dx.doi.org/10.1007/s00438-005-0048-x.

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30

Igouzoul, A., J. Douchin, E. Audet-Walsh, F. Boisvert y V. Giroux. "A10 PROLINE METABOLISM AFFECTS CANCER STEM CELLS IN ESOPHAGEAL SQUAMOUS CELL CARCINOMA". Journal of the Canadian Association of Gastroenterology 7, Supplement_1 (14 de febrero de 2024): 6. http://dx.doi.org/10.1093/jcag/gwad061.010.

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Abstract Background Esophageal squamous cell carcinoma (ESCC) is highly deadly with a 5-year survival rate of only 16%, partly due to treatment resistance. Resistance is associated, among others, with the presence of cancer stem cells (CSC). Previous work in the laboratory has shown that prolonged exposure to anticancer treatments such as radiation and/or 5-FU leads to increased number of CSCs. Interestingly, disruption of amino acid metabolism, especially decreased proline levels, has been observed in treated cells. Proline is a non-essential amino acid that can either be uptake from the environment or synthesized from glutamate or ornithine. However, its role in cancer cells remains poorly understood and controversial. Aims Therefore, my project aims at determining the role of proline metabolism in CSC abundance and tumoral properties in ESCC. Methods Using ESCC cell lines, TE11 and TE15, we stimulated proline metabolism by adding proline to the media or inhibited its catabolism using L-THFA. L-THFA forces proline accumulation in the cell. We then conducted flow cytometry to quantify CSC proportion, proliferation assay, spheroid formation assay and spheroids included in collagen for migration and invasion assay. Results First, the stimulation of proline metabolism decreased the proportion of CSCs in flow cytometry. These results align with our initial observations, where CSC-enriched cells exhibited reduced proline levels. Second, the inhibition of proline catabolism by L-THFA had the opposite effect, namely an increase in the proportion of CSC. Interestingly, these changes in the proportion of CSCs induced by proline or L-THFA translated into changes in clonogenic potential, a capacity typically associated with stem cells. Indeed, limiting dilution spheroids formation assays showed that proline decreased while L-THFA increased the number of formed spheroids. Since spheroids formation is linked to the presence of CSC, this provides new evidence of the impact of proline metabolism on CSC characteristics. Finally, L-THFA treatments drastically increased migratory and invasive abilities in 3D spheroid models compared to untreated or proline-treated conditions. Conclusions In conclusion, our results suggest that proline metabolism is implicated in the enrichment of cancer stem cells as well as in their functions. Funding Agencies CAG, CIHRinnovation.ca ; Centre de recherche CHUS ; FMSS ; Canada Research Chairs

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31

Huberman, Lori B., Vincent W. Wu, David J. Kowbel, Juna Lee, Chris Daum, Igor V. Grigoriev, Ronan C. O’Malley y N. Louise Glass. "DNA affinity purification sequencing and transcriptional profiling reveal new aspects of nitrogen regulation in a filamentous fungus". Proceedings of the National Academy of Sciences 118, n.º 13 (22 de marzo de 2021): e2009501118. http://dx.doi.org/10.1073/pnas.2009501118.

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Sensing available nutrients and efficiently utilizing them is a challenge common to all organisms. The model filamentous fungus Neurospora crassa is capable of utilizing a variety of inorganic and organic nitrogen sources. Nitrogen utilization in N. crassa is regulated by a network of pathway-specific transcription factors that activate genes necessary to utilize specific nitrogen sources in combination with nitrogen catabolite repression regulatory proteins. We identified an uncharacterized pathway-specific transcription factor, amn-1, that is required for utilization of the nonpreferred nitrogen sources proline, branched-chain amino acids, and aromatic amino acids. AMN-1 also plays a role in regulating genes involved in responding to the simple sugar mannose, suggesting an integration of nitrogen and carbon metabolism. The utilization of nonpreferred nitrogen sources, which require metabolic processing before being used as a nitrogen source, is also regulated by the nitrogen catabolite regulator NIT-2. Using RNA sequencing combined with DNA affinity purification sequencing, we performed a survey of the role of NIT-2 and the pathway-specific transcription factors NIT-4 and AMN-1 in directly regulating genes involved in nitrogen utilization. Although previous studies suggested promoter binding by both a pathway-specific transcription factor and NIT-2 may be necessary for activation of nitrogen-responsive genes, our data show that pathway-specific transcription factors regulate genes involved in the catabolism of specific nitrogen sources, while NIT-2 regulates genes involved in utilization of all nonpreferred nitrogen sources, such as nitrogen transporters. Together, these transcription factors form a nutrient sensing network that allows N. crassa cells to regulate nitrogen utilization.

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Silva, Nicola, Maikel Castellano-Pozo, Kenichiro Matsuzaki, Consuelo Barroso, Monica Roman-Trufero, Hannah Craig, Darren R. Brooks, R. Elwyn Isaac, Simon J. Boulton y Enrique Martinez-Perez. "Proline-specific aminopeptidase P prevents replication-associated genome instability". PLOS Genetics 18, n.º 1 (26 de enero de 2022): e1010025. http://dx.doi.org/10.1371/journal.pgen.1010025.

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Genotoxic stress during DNA replication constitutes a serious threat to genome integrity and causes human diseases. Defects at different steps of DNA metabolism are known to induce replication stress, but the contribution of other aspects of cellular metabolism is less understood. We show that aminopeptidase P (APP1), a metalloprotease involved in the catabolism of peptides containing proline residues near their N-terminus, prevents replication-associated genome instability. Functional analysis of C. elegans mutants lacking APP-1 demonstrates that germ cells display replication defects including reduced proliferation, cell cycle arrest, and accumulation of mitotic DSBs. Despite these defects, app-1 mutants are competent in repairing DSBs induced by gamma irradiation, as well as SPO-11-dependent DSBs that initiate meiotic recombination. Moreover, in the absence of SPO-11, spontaneous DSBs arising in app-1 mutants are repaired as inter-homologue crossover events during meiosis, confirming that APP-1 is not required for homologous recombination. Thus, APP-1 prevents replication stress without having an apparent role in DSB repair. Depletion of APP1 (XPNPEP1) also causes DSB accumulation in mitotically-proliferating human cells, suggesting that APP1’s role in genome stability is evolutionarily conserved. Our findings uncover an unexpected role for APP1 in genome stability, suggesting functional connections between aminopeptidase-mediated protein catabolism and DNA replication.

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Iyer, Suresh y Allan Caplan. "Products of Proline Catabolism Can Induce Osmotically Regulated Genes in Rice". Plant Physiology 116, n.º 1 (1 de enero de 1998): 203–11. http://dx.doi.org/10.1104/pp.116.1.203.

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Curtis, Jason, Georgia Shearer y Daniel H. Kohl. "Bacteroid Proline Catabolism Affects N2 Fixation Rate of Drought-Stressed Soybeans". Plant Physiology 136, n.º 2 (24 de septiembre de 2004): 3313–18. http://dx.doi.org/10.1104/pp.104.044024.

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35

Glenn, A. "The transport and catabolism of ?-proline by cowpea Rhizobium NGR 234". FEMS Microbiology Letters 82, n.º 3 (15 de agosto de 1991): 307–12. http://dx.doi.org/10.1016/0378-1097(91)90279-j.

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36

Gloux, Karine y Daniel Le Rudulier. "Transport and catabolism of proline betaine in salt-stressed Rhizobium meliloti". Archives of Microbiology 151, n.º 2 (enero de 1989): 143–48. http://dx.doi.org/10.1007/bf00414429.

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37

Cabassa-Hourton, Cécile, Peter Schertl, Marianne Bordenave-Jacquemin, Kaouthar Saadallah, Anne Guivarc'h, Sandrine Lebreton, Séverine Planchais et al. "Proteomic and functional analysis of proline dehydrogenase 1 link proline catabolism to mitochondrial electron transport in Arabidopsis thaliana". Biochemical Journal 473, n.º 17 (30 de agosto de 2016): 2623–34. http://dx.doi.org/10.1042/bcj20160314.

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Molecular and biochemical analyses indicate a key role of proline dehydrogenase 1 in proline oxidation. ProDH1 binds to mitochondrial membranes, is part of small respiratory chain complex and delivers its electrons to the respiratory chain.

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38

Oh, Glenda Guek Khim, Brendan M. O’Leary, Santiago Signorelli y A. Harvey Millar. "Alternative oxidase (AOX) 1a and 1d limit proline-induced oxidative stress and aid salinity recovery in Arabidopsis". Plant Physiology 188, n.º 3 (17 de diciembre de 2021): 1521–36. http://dx.doi.org/10.1093/plphys/kiab578.

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Abstract Proline (Pro) catabolism and reactive oxygen species production have been linked in mammals and Caenorhabditis elegans, while increases in leaf respiration rate follow Pro exposure in plants. Here, we investigated how alternative oxidases (AOXs) of the mitochondrial electron transport chain accommodate the large, atypical flux resulting from Pro catabolism and limit oxidative stress during Pro breakdown in mature Arabidopsis (Arabidopsis thaliana) leaves. Following Pro treatment, AOX1a and AOX1d accumulate at transcript and protein levels, with AOX1d approaching the level of the typically dominant AOX1a isoform. We therefore sought to determine the function of both AOX isoforms under Pro respiring conditions. Oxygen consumption rate measurements in aox1a and aox1d leaves suggested these AOXs can functionally compensate for each other to establish enhanced AOX catalytic capacity in response to Pro. Generation of aox1a.aox1d lines showed complete loss of AOX proteins and activity upon Pro treatment, yet full respiratory induction in response to Pro remained possible via the cytochrome pathway. However, aox1a.aox1d leaves displayed symptoms of elevated oxidative stress and suffered increased oxidative damage during Pro metabolism compared to the wild-type (WT) or the single mutants. During recovery from salt stress, when relatively high rates of Pro catabolism occur naturally, photosynthetic rates in aox1a.aox1d recovered slower than in the WT or the single aox lines, showing that both AOX1a and AOX1d are beneficial for cellular metabolism during Pro drawdown following osmotic stress. This work provides physiological evidence of a beneficial role for AOX1a but also the less studied AOX1d isoform in allowing safe catabolism of alternative respiratory substrates like Pro.

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Falcioni, Francesco, Lars M. Blank, Oliver Frick, Andreas Karau, Bruno Bühler y Andreas Schmid. "Proline Availability Regulates Proline-4-Hydroxylase Synthesis and Substrate Uptake in Proline-Hydroxylating Recombinant Escherichia coli". Applied and Environmental Microbiology 79, n.º 9 (1 de marzo de 2013): 3091–100. http://dx.doi.org/10.1128/aem.03640-12.

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ABSTRACTMicrobial physiology plays a crucial role in whole-cell biotransformation, especially for redox reactions that depend on carbon and energy metabolism. In this study, regio- and enantio-selective proline hydroxylation with recombinantEscherichia coliexpressing proline-4-hydroxylase (P4H) was investigated with respect to its interconnectivity to microbial physiology and metabolism. P4H production was found to depend on extracellular proline availability and on codon usage. Medium supplementation with proline did not alterp4hmRNA levels, indicating that P4H production depends on the availability of charged prolyl-tRNAs. Increasing the intracellular levels of soluble P4H did not result in an increase in resting cell activities above a certain threshold (depending on growth and assay temperature). Activities up to 5-fold higher were reached with permeabilized cells, confirming that host physiology and not the intracellular level of active P4H determines the achievable whole-cell proline hydroxylation activity. Metabolic flux analysis revealed that tricarboxylic acid cycle fluxes in growing biocatalytically active cells were significantly higher than proline hydroxylation rates. Remarkably, a catalysis-induced reduction of substrate uptake was observed, which correlated with reduced transcription ofputAandputP, encoding proline dehydrogenase and the major proline transporter, respectively. These results provide evidence for a strong interference of catalytic activity with the regulation of proline uptake and metabolism. In terms of whole-cell biocatalyst efficiency, proline uptake and competition of P4H with proline catabolism are considered the most critical factors.

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Nakada, Yuji, Takayuki Nishijyo y Yoshifumi Itoh. "Divergent Structure and Regulatory Mechanism of Proline Catabolic Systems: Characterization of the putAP Proline Catabolic Operon of Pseudomonas aeruginosa PAO1 and Its Regulation by PruR, an AraC/XylS Family Protein". Journal of Bacteriology 184, n.º 20 (15 de octubre de 2002): 5633–40. http://dx.doi.org/10.1128/jb.184.20.5633-5640.2002.

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ABSTRACT Pseudomonas aeruginosa PAO1 utilizes proline as the sole source of carbon and nitrogen via a bifunctional enzyme (the putA gene product) that has both proline dehydrogenase (EC 1.5.99.8) and pyrroline 5-carboxylate dehydrogenase (EC 1.5.1.12) activities. We characterized the pruR-putAP loci encoding the proline catabolic system of this strain. In contrast to the putA and putP (encoding proline permease) genes of other gram- negative bacteria, which are located at divergent or separate loci, Northern blotting demonstrated that the two genes form an operon in strain PAO1. While the phylogenetic lineage of the PutP protein of strain PAO1 was related to that of the origin (80% identity to the P. putida counterpart), PutA of PAO1 (PutAPAO) was rather distantly related (47% identity) to the P. putida counterpart. Moreover, unlike the PutA proteins of P. putida and enteric bacteria, PutAPAO appeared to lack a regulatory function. Upstream of the putAP operon, the divergent PA0781 gene specified a hypothetical outer membrane protein with a molecular weight of 74,202. This gene appeared to be dispensable for proline utilization as indicated by the normal growth of a knockout mutant of PA0781 on medium containing proline. The pruR (proline utilization regulator) gene immediately upstream of PA0781 encoded a transcriptional activator of the AraC/XylS protein family and mediated the proline-responsive expression of putAP. Primer extension studies identified a PruR-dependent promoter responsive to proline in the 5′-flanking region of putA. Thus, the proline utilization system of P. aeruginosa differs from that of P. putida with respect to putA structure, the organization of the putAP genes, and the regulatory mechanism of putA expression.

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Vílchez, Susana, Lázaro Molina, Cayo Ramos y Juan L. Ramos. "Proline Catabolism by Pseudomonas putida: Cloning, Characterization, and Expression of the put Genes in the Presence of Root Exudates". Journal of Bacteriology 182, n.º 1 (1 de enero de 2000): 91–99. http://dx.doi.org/10.1128/jb.182.1.91-99.2000.

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ABSTRACT Pseudomonas putida KT2442 is a root-colonizing strain which can use proline, one of the major components in root exudates, as its sole carbon and nitrogen source. A P. putida mutant unable to grow with proline as the sole carbon and nitrogen source was isolated after random mini-Tn5–Km mutagenesis. The mini-Tn5 insertion was located at the putAgene, which is adjacent to and divergent from the putPgene. The putA gene codes for a protein of 1,315 amino acid residues which is homologous to the PutA protein of Escherichia coli, Salmonella enterica serovar Typhimurium,Rhodobacter capsulatus, and several Rhizobiumstrains. The central part of P. putida PutA showed homology to the proline dehydrogenase of Saccharomyces cerevisiae and Drosophila melanogaster, whereas the C-terminal end was homologous to the pyrroline-5-carboxylate dehydrogenase of S. cerevisiae and a number of aldehyde dehydrogenases. This suggests that in P. putida, both enzymatic steps for proline conversion to glutamic acid are catalyzed by a single polypeptide. The putP gene was homologous to the putP genes of several prokaryotic microorganisms, and its gene product is an integral inner-membrane protein involved in the uptake of proline. The expression of both genes was induced by proline added in the culture medium and was regulated by PutA. In a P. putida putA-deficient background, expression of bothputA and putP genes was maximal and proline independent. Corn root exudates collected during 7 days also strongly induced the P. putida put genes, as determined by using fusions of the put promoters to ′lacZ. The induction ratio for the putA promoter (about 20-fold) was 6-fold higher than the induction ratio for the putPpromoter.

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Scazzocchio, Claudio, Victoria Gavrias, Beatriz Cubero, Cristina Panozzo, Martine Mathieu y Béatrice Felenbok. "Carbon catabolite repression in Aspergillus nidulans: a review". Canadian Journal of Botany 73, S1 (31 de diciembre de 1995): 160–66. http://dx.doi.org/10.1139/b95-240.

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We describe the experimental methodology that led to the discovery of the creA gene in Aspergillus nidulans. This gene codes for a transcriptional repressor mediating carbon catabolite repression in many pathways in this organism. We compare both the mode and the mechanism of action in two pathways subject to CreA-mediated repression. The genes comprising the ethanol regulon are subject to carbon catabolite repression independently of the nitrogen source, while the genes involved in proline utilization are repressed by glucose only when a repressing nitrogen source is also present. In the ethanol regulon, CreA drastically represses the expression of the positive regulatory gene alcR, thus preventing the expression of the structural genes. Direct repression of the structural genes is also existant. In the proline utilization pathway, repression operates directly at the level of the structural genes. In the ethanol regulon, CreA prevents the self-induction of alcR and the induction of the structural genes by competing with the binding of the AlcR protein. In proline gene cluster, CreA does not interfere with induction mediated by PrnA but with the activity of an unknown and more general transcription factor. Key words: carbon catabolite repression, ascomycetes, Zn fingers.

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Quintero, María José, Alicia María Muro-Pastor, Antonia Herrero y Enrique Flores. "Arginine Catabolism in the CyanobacteriumSynechocystis sp. Strain PCC 6803 Involves the Urea Cycle and Arginase Pathway". Journal of Bacteriology 182, n.º 4 (15 de febrero de 2000): 1008–15. http://dx.doi.org/10.1128/jb.182.4.1008-1015.2000.

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ABSTRACT Cells of the unicellular cyanobacterium Synechocystissp. strain PCC 6803 supplemented with micromolar concentrations ofl-[14C]arginine took up, concentrated, and catabolized this amino acid. Metabolism ofl-[14C]arginine generated a set of labeled amino acids that included argininosuccinate, citrulline, glutamate, glutamine, ornithine, and proline. Production of [14C]ornithine preceded that of [14C]citrulline, and the patterns of labeled amino acids were similar in cells incubated withl-[14C]ornithine, suggesting that the reaction of arginase, rendering ornithine and urea, is the main initial step in arginine catabolism. Ornithine followed two metabolic pathways: (i) conversion into citrulline, catalyzed by ornithine carbamoyltransferase, and then, with incorporation of aspartate, conversion into argininosuccinate, in a sort of urea cycle, and (ii) a sort of arginase pathway rendering glutamate (and glutamine) via Δ1pyrroline-5-carboxylate and proline. Consistently with the proposed metabolic scheme (i) an argF (ornithine carbamoyltransferase) insertional mutant was impaired in the production of [14C]citrulline from [14C]arginine; (ii) a proC (Δ1pyrroline-5-carboxylate reductase) insertional mutant was impaired in the production of [14C]proline, [14C]glutamate, and [14C]glutamine from [14C]arginine or [14C]ornithine; and (iii) a putA (proline oxidase) insertional mutant did not produce [14C]glutamate froml-[14C]arginine,l-[14C]ornithine, orl-[14C]proline. Mutation of two open reading frames (sll0228 and sll1077) putatively encoding proteins homologous to arginase indicated, however, that none of these proteins was responsible for the arginase activity detected in this cyanobacterium, and mutation of argD(N-acetylornithine aminotransferase) suggested that this transaminase is not important in the production of Δ1pyrroline-5-carboxylate from ornithine. The metabolic pathways proposed to explain [14C]arginine catabolism also provide a rationale for understanding how nitrogen is made available to the cell after mobilization of cyanophycin [multi-l-arginyl-poly(l-aspartic acid)], a reserve material unique to cyanobacteria.

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Wei, Tong-Lu, Ze-Xian Wang, Yu-Fan He, Shuo Xue, Shuai-Qi Zhang, Mao-Song Pei, Hai-Nan Liu, Yi-He Yu y Da-Long Guo. "Proline synthesis and catabolism-related genes synergistically regulate proline accumulation in response to abiotic stresses in grapevines". Scientia Horticulturae 305 (noviembre de 2022): 111373. http://dx.doi.org/10.1016/j.scienta.2022.111373.

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Dillon, E. Lichar, Darrell A. Knabe y Guoyao Wu. "Lactate inhibits citrulline and arginine synthesis from proline in pig enterocytes". American Journal of Physiology-Gastrointestinal and Liver Physiology 276, n.º 5 (1 de mayo de 1999): G1079—G1086. http://dx.doi.org/10.1152/ajpgi.1999.276.5.g1079.

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Hypocitrullinemia and hypoargininemia but hyperprolinemia are associated with elevated plasma concentration of lactate in infants. Because the small intestine may be a major organ for initiating proline catabolism via proline oxidase in the body and is the major source of circulating citrulline and arginine in neonates, we hypothesized that lactate is an inhibitor of intestinal synthesis of citrulline and arginine from proline. To test this hypothesis, jejunum was obtained from 14-day-old suckling pigs for preparation of enterocyte mitochondria and metabolic studies. Mitochondria were used for measuring proline oxidase activity in the presence of 0–10 mMl-lactate. For metabolic studies, enterocytes were incubated at 37°C for 30 min in Krebs bicarbonate buffer (pH 7.4) containing 5 mMd-glucose, 2 mMl-glutamine, 2 mMl-[U-14C]proline, and 0, 1, 5, or 10 mM l-lactate. Kinetics analysis revealed noncompetitive inhibition of intestinal proline oxidase by lactate (decreased maximal velocity and unaltered Michaelis constant). Lactate had no effect on either activities of other enzymes for arginine synthesis from proline or proline uptake by enterocytes but decreased the synthesis of ornithine, citrulline, and arginine from proline in a concentration-dependent manner. These results demonstrate that lactate decreased intestinal synthesis of citrulline and arginine from proline via an inhibition of proline oxidase and provide a biochemical basis for explaining hyperprolinemia, hypocitrullinemia, and hypoargininemia in infants with hyperlactacidemia.

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Nuxoll, Austin S., Steven M. Halouska, Marat R. Sadykov, Mark L. Hanke, Kenneth W. Bayles, Tammy Kielian, Robert Powers y Paul D. Fey. "CcpA Regulates Arginine Biosynthesis in Staphylococcus aureus through Repression of Proline Catabolism". PLoS Pathogens 8, n.º 11 (29 de noviembre de 2012): e1003033. http://dx.doi.org/10.1371/journal.ppat.1003033.

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Mitchell, Heidi J., Michael A. Ayliffe, Khalid Y. Rashid y Anthony J. Pryor. "A rust-inducible gene from flax (fis1) is involved in proline catabolism". Planta 223, n.º 2 (4 de agosto de 2005): 213–22. http://dx.doi.org/10.1007/s00425-005-0079-x.

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48

Silao, Fitz Gerald S., Meliza Ward, Kicki Ryman, Axel Wallström, Björn Brindefalk, Klas Udekwu y Per O. Ljungdahl. "Mitochondrial proline catabolism activates Ras1/cAMP/PKA-induced filamentation in Candida albicans". PLOS Genetics 15, n.º 2 (11 de febrero de 2019): e1007976. http://dx.doi.org/10.1371/journal.pgen.1007976.

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49

Li, Chunling, Fei Sun, Hoonsik Cho, Vamshi Yelavarthi, Changmo Sohn, Chuan He, Olaf Schneewind y Taeok Bae. "CcpA Mediates Proline Auxotrophy and Is Required for Staphylococcus aureus Pathogenesis". Journal of Bacteriology 192, n.º 15 (2 de junio de 2010): 3883–92. http://dx.doi.org/10.1128/jb.00237-10.

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ABSTRACT Human clinical isolates of Staphylococcus aureus, for example, strains Newman and N315, cannot grow in the absence of proline, albeit their sequenced genomes harbor genes for two redundant proline synthesis pathways. We show here that under selective pressure, S. aureus Newman generates proline-prototrophic variants at a frequency of 3 × 10−6, introducing frameshift and missense mutations in ccpA or IS1811 insertions in ptsH, two regulatory genes that carry out carbon catabolite repression (CCR) in staphylococci and other Gram-positive bacteria. S. aureus Newman variants with mutations in rocF (arginase), rocD (ornithine aminotransferase), and proC (Δ1-pyrroline 5-carboxylate [P5C] reductase) are unable to generate proline-prototrophic variants, whereas a variant with a mutation in ocd (ornithine cyclodeaminase) is unaffected. Transposon insertion in ccpA also restored proline prototrophy. CcpA was shown to repress transcription of rocF and rocD, encoding the first two enzymes, but not of proC, encoding the third and final enzyme in the P5C reductase pathway. CcpA bound to the upstream regions of rocF and rocD but not to that of proC. CcpA's binding to the upstream regions was greatly enhanced by phosphorylated HPr. The CCR-mediated proline auxotrophy was lifted when nonpreferred carbohydrates were used as the sole carbon source. The ccpA mutant displayed reduced staphylococcal load and replication in a murine model of staphylococcal abscess formation, indicating that carbon catabolite repression presents an important pathogenesis strategy of S. aureus infections.

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50

Lee, Tse-Min y Chia-Hsiung Liu. "Regulation of NaCl-induced proline accumulation by calmodulin via modification of proline dehydrogenase activity in Ulva fasciata (Chlorophyta)". Functional Plant Biology 26, n.º 6 (1999): 595. http://dx.doi.org/10.1071/pp99025.

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This paper examined the role of proline dehydrogenase (PDH; EC 1.4.3.1) in salinity-induced (adjusted by increasing NaCl contents in seawater) proline accumulation in the marine chlorophyte Ulva fasciata Delile, and also determined whether calmodulin modulates proline accumulation via a change in the activity and kinetic property of PDH. Upon exposure to varying salinity (30–120‰, that is, 317.9–1858 mМ NaCl in seawater) for 9 h, proline levels increased with increasing salinity, and were highly correlated with salinity (r2 = 0.97). In contrast, PDH-specific activity decreased with increasing salinity, and was inversely related with external salinity (r2 = 0.95) and proline levels (r2 = 0.80). When exposed to 60‰ salinity (831.3 mМ NaCl), PDH-specific activity decreased at hour 2, and proline levels increased at hour 3, as compared to the 35‰ (403.5 mМ NaCl) control. The addition of chlorpromazine (CP, 0.8 µМ) or trifluoperazine (TFP, 1 µМ), both calmodulin binding inhibitors, in seawater enhanced the increase in the levels of proline, but did not affect its Km value. It also enhanced the decrease in the specific activity and Vmax value of PDH in the 60‰-treated thallus discs. Overall, the reduction in catabolism via a decrease in PDH activity is associated with the NaCl-induced proline accumulation in U. fasciata, and the calmodulin-mediated signal transduction might be negatively involved in the regulation of proline accumulation via a modification in PDH properties.

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