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Littérature scientifique sur le sujet « Pyrroline-5-carboxylate complex »

Auteur : Grafiati

Publié le 25 mai 2024

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Articles de revues sur le sujet "Pyrroline-5-carboxylate complex"

Terao, Yukiyasu, Shigeru Nakamori, and Hiroshi Takagi. "Gene Dosage Effect of l-Proline Biosynthetic Enzymes on l-Proline Accumulation and Freeze Tolerance in Saccharomyces cerevisiae." Applied and Environmental Microbiology 69, no. 11 (2003): 6527–32. http://dx.doi.org/10.1128/aem.69.11.6527-6532.2003.

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ABSTRACT We have previously reported that l-proline has cryoprotective activity in Saccharomyces cerevisiae. A freeze-tolerant mutant with l-proline accumulation was recently shown to carry an allele of the PRO1 gene encoding γ-glutamyl kinase, which resulted in a single amino acid substitution (Asp154Asn). Interestingly, this mutation enhanced the activities of γ-glutamyl kinase and γ-glutamyl phosphate reductase, both of which catalyze the first two steps of l-proline synthesis and which together may form a complex in vivo. Here, we found that the Asp154Asn mutant γ-glutamyl kinase was more thermostable than the wild-type enzyme, which suggests that this mutation elevated the apparent activities of two enzymes through a stabilization of the complex. We next examined the gene dosage effect of three l-proline biosynthetic enzymes, including Δ1-pyrroline-5-carboxylate reductase, which converts Δ1-pyrroline-5-carboxylate into l-proline, on l-proline accumulation and freeze tolerance in a non-l-proline-utilizing strain. Overexpression of the wild-type enzymes has no influence on l-proline accumulation, which suggests that the complex is very unstable in nature. However, co-overexpression of the mutant γ-glutamyl kinase and the wild-type γ-glutamyl phosphate reductase was effective for l-proline accumulation, probably due to a stabilization of the complex. These results indicate that both enzymes, not Δ1-pyrroline-5-carboxylate reductase, are rate-limiting enzymes in yeast cells. A high tolerance for freezing clearly correlated with higher levels of l-proline in yeast cells. Our findings also suggest that, in addition to its cryoprotective activity, intracellular l-proline could protect yeast cells from damage by oxidative stress. The approach described here provides a valuable method for breeding novel yeast strains that are tolerant of both freezing and oxidative stresses.

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Ion, Bogdan F., Mohamed M. Aboelnga та James W. Gauld. "Insights from molecular dynamics on substrate binding and effects of active site mutations in Δ1-pyrroline-5-carboxylate dehydrogenase". Canadian Journal of Chemistry 94, № 12 (2016): 1151–62. http://dx.doi.org/10.1139/cjc-2016-0286.

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The NAD+-dependent enzyme, Δ1-pyrroline-5-carboxylate dehydrogenase (P5CDH), has an important role in proline and hydroxyproline catabolism for humans. Specifically, this aldehyde dehydrogenase is responsible for the oxidation of both l-glutamate-γ-semialdehyde (GSA) and 4-erythro-hydroxy-l-glutamate-γ-semialdehyde (4-OH-GSA) to their respective l-glutamate product forms. We have performed a detailed molecular dynamics (MD) study of both the reactant and product complex structures of P5CDH to gain insights into ligand binding (i.e., GSA, 4-OH-GSA, NAD+, GLU) in the active site. Moreover, our investigations were further extended to examine the structural impact of S352L, S352A, and E314A mutations on the deficiency in the P5CDH enzymatic activity. Our in silico mutation analysis indicated that the conserved Glu447 has significantly shifted in both the S352L and E314A mutants, causing NAD+ to be displaced from its predictive orientation in the binding site and hence forming a catalytically inactive enzyme. However in the case of S352A, the catalytic site including the oxyanion hole and Cys348 remain virtually unchanged, and the coenzyme maintains its binding position.

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Kretz, Rita, Bita Bozorgmehr, Mohamad Hasan Kariminejad, et al. "Defect in proline synthesis: pyrroline-5-carboxylate reductase 1 deficiency leads to a complex clinical phenotype with collagen and elastin abnormalities." Journal of Inherited Metabolic Disease 34, no. 3 (2011): 731–39. http://dx.doi.org/10.1007/s10545-011-9319-3.

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Pallag, Gergely, Sara Nazarian, Dora Ravasz, et al. "Proline Oxidation Supports Mitochondrial ATP Production When Complex I Is Inhibited." International Journal of Molecular Sciences 23, no. 9 (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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Silao, Fitz Gerald S., Tong Jiang, Biborka Bereczky-Veress, et al. "Proline catabolism is a key factor facilitating Candida albicans pathogenicity." PLOS Pathogens 19, no. 11 (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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Lagautriere, Thomas, Ghader Bashiri та Edward N. Baker. "Use of a “silver bullet” to resolve crystal lattice dislocation disorder: A cobalamin complex of Δ1-pyrroline-5-carboxylate dehydrogenase from Mycobacterium tuberculosis". Journal of Structural Biology 189, № 2 (2015): 153–57. http://dx.doi.org/10.1016/j.jsb.2014.12.007.

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Sun, Chenglong, Tiegang Li, Xiaowei Song, et al. "Spatially resolved metabolomics to discover tumor-associated metabolic alterations." Proceedings of the National Academy of Sciences 116, no. 1 (2018): 52–57. http://dx.doi.org/10.1073/pnas.1808950116.

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Characterization of tumor metabolism with spatial information contributes to our understanding of complex cancer metabolic reprogramming, facilitating the discovery of potential metabolic vulnerabilities that might be targeted for tumor therapy. However, given the metabolic variability and flexibility of tumors, it is still challenging to characterize global metabolic alterations in heterogeneous cancer. Here, we propose a spatially resolved metabolomics approach to discover tumor-associated metabolites and metabolic enzymes directly in their native state. A variety of metabolites localized in different metabolic pathways were mapped by airflow-assisted desorption electrospray ionization mass spectrometry imaging (AFADESI-MSI) in tissues from 256 esophageal cancer patients. In combination with in situ metabolomics analysis, this method provided clues into tumor-associated metabolic pathways, including proline biosynthesis, glutamine metabolism, uridine metabolism, histidine metabolism, fatty acid biosynthesis, and polyamine biosynthesis. Six abnormally expressed metabolic enzymes that are closely associated with the altered metabolic pathways were further discovered in esophageal squamous cell carcinoma (ESCC). Notably, pyrroline-5-carboxylate reductase 2 (PYCR2) and uridine phosphorylase 1 (UPase1) were found to be altered in ESCC. The spatially resolved metabolomics reveal what occurs in cancer at the molecular level, from metabolites to enzymes, and thus provide insights into the understanding of cancer metabolic reprogramming.

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Yildiz, Ibrahim. "Computational insights on the hydride and proton transfer mechanisms of L-proline dehydrogenase." PLOS ONE 18, no. 11 (2023): e0290901. http://dx.doi.org/10.1371/journal.pone.0290901.

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L-Proline dehydrogenase (ProDH) is a flavin-dependent oxidoreductase, which catalyzes the oxidation of L-proline to (S)-1-pyrroline-5-carboxylate. Based on the experimental studies, a stepwise proton and hydride transfer mechanism is supported. According to this mechanism, the amino group of L-proline is deprotonated by a nearby Lys residue, which is followed by the hydride transfer process from C5 position of L-proline to N5 position of isoalloxazine ring of FAD. It was concluded that the hydride transfer step is rate limiting in the reductive half-reaction, however, in the overall reaction, the oxidation of FAD is the rate limiting step. In this study, we performed a computational mechanistic investigation based on ONIOM method to elucidate the mechanism of the reductive half-reaction corresponding to the oxidation of L-proline into iminoproline. Our calculations support the stepwise mechanism in which the deprotonation occurs initially as a fast step as result of a proton transfer from L-proline to the Lys residue. Subsequently, a hydride ion transfers from L-proline to FAD with a higher activation barrier. The enzyme-product complex showed a strong interaction between reduced FAD and iminoproline, which might help to explain why a step in the oxidative half-reaction is rate-limiting.

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DelVecchio, Vito G., Joseph P. Connolly, Timothy G. Alefantis, et al. "Proteomic Profiling and Identification of Immunodominant Spore Antigens of Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis." Applied and Environmental Microbiology 72, no. 9 (2006): 6355–63. http://dx.doi.org/10.1128/aem.00455-06.

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ABSTRACT Differentially expressed and immunogenic spore proteins of the Bacillus cereus group of bacteria, which includes Bacillus anthracis, Bacillus cereus, and Bacillus thuringiensis, were identified. Comparative proteomic profiling of their spore proteins distinguished the three species from each other as well as the virulent from the avirulent strains. A total of 458 proteins encoded by 232 open reading frames were identified by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry analysis for all the species. A number of highly expressed proteins, including elongation factor Tu (EF-Tu), elongation factor G, 60-kDa chaperonin, enolase, pyruvate dehydrogenase complex, and others exist as charge variants on two-dimensional gels. These charge variants have similar masses but different isoelectric points. The majority of identified proteins have cellular roles associated with energy production, carbohydrate transport and metabolism, amino acid transport and metabolism, posttranslational modifications, and translation. Novel vaccine candidate proteins were identified using B. anthracis polyclonal antisera from humans postinfected with cutaneous anthrax. Fifteen immunoreactive proteins were identified in B. anthracis spores, whereas 7, 14, and 7 immunoreactive proteins were identified for B. cereus and in the virulent and avirulent strains of B. thuringiensis spores, respectively. Some of the immunodominant antigens include charge variants of EF-Tu, glyceraldehyde-3-phosphate dehydrogenase, dihydrolipoamide acetyltransferase, Δ-1-pyrroline-5-carboxylate dehydrogenase, and a dihydrolipoamide dehydrogenase. Alanine racemase and neutral protease were uniquely immunogenic to B. anthracis. Comparative analysis of the spore immunome will be of significance for further nucleic acid- and immuno-based detection systems as well as next-generation vaccine development.

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Lewoniewska, Sylwia, Ilona Oscilowska, Antonella Forlino, and Jerzy Palka. "Understanding the Role of Estrogen Receptor Status in PRODH/POX-Dependent Apoptosis/Survival in Breast Cancer Cells." Biology 10, no. 12 (2021): 1314. http://dx.doi.org/10.3390/biology10121314.

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It has been suggested that activation of estrogen receptor α (ER α) stimulates cell proliferation. In contrast, estrogen receptor β (ER β) has anti-proliferative and pro-apoptotic activity. Although the role of estrogens in estrogen receptor-positive breast cancer progression has been well established, the mechanism of their effect on apoptosis is not fully understood. It has been considered that ER status of breast cancer cells and estrogen availability might determine proline dehydrogenase/proline oxidase (PRODH/POX)-dependent apoptosis. PRODH/POX is a mitochondrial enzyme that converts proline into pyrroline-5-carboxylate (P5C). During this process, ATP (adenosine triphosphate) or ROS (reactive oxygen species) are produced, facilitating cell survival or death, respectively. However, the critical factor in driving PRODH/POX-dependent functions is proline availability. The amount of this amino acid is regulated at the level of prolidase (proline releasing enzyme), collagen biosynthesis (proline utilizing process), and glutamine, glutamate, α-ketoglutarate, and ornithine metabolism. Estrogens were found to upregulate prolidase activity and collagen biosynthesis. It seems that in estrogen receptor-positive breast cancer cells, prolidase supports proline for collagen biosynthesis, limiting its availability for PRODH/POX-dependent apoptosis. Moreover, lack of free proline (known to upregulate the transcriptional activity of hypoxia-inducible factor 1, HIF-1) contributes to downregulation of HIF-1-dependent pro-survival activity. The complex regulatory mechanism also involves PRODH/POX expression and activity. It is induced transcriptionally by p53 and post-transcriptionally by AMPK (AMP-activated protein kinase), which is regulated by ERs. The review also discusses the role of interconversion of proline/glutamate/ornithine in supporting proline to PRODH/POX-dependent functions. The data suggest that PRODH/POX-induced apoptosis is dependent on ER status in breast cancer cells.

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