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Bisello G, Saris CG, Franchini R, Verbeek MM, Willemsen MA, Perduca M, Bertoldi M. An attenuated, adult case of AADC deficiency demonstrated by protein characterization. Mol Genet Metab Rep 2024; 39:101071. [PMID: 38524666 PMCID: PMC10958467 DOI: 10.1016/j.ymgmr.2024.101071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2024] [Revised: 03/10/2024] [Accepted: 03/10/2024] [Indexed: 03/26/2024] Open
Abstract
A case of an adult with borderline AADC deficiency symptoms is presented here. Genetic analysis revealed that the patient carries two AADC variants (NM_000790.3: c.1040G > A and c.679G > C) in compound heterozygosis, resulting in p.Arg347Gln and p.Glu227Gln amino acid alterations. While p.Arg347Gln is a known pathogenic variant, p.Glu227Gln is unknown. Combining clinical features to bioinformatic and molecular characterization of the AADC protein population of the patient (p.Arg347Gln/p.Arg347Gln homodimer, p.Glu227Gln/p.Glu227Gln homodimer, and p.Glu227Gln/p.Arg347Gln heterodimer), we determined that: i) the p.Arg347Gln/p.Arg347Gln homodimer is inactive since the alteration affects a catalytically essential structural element at the active site, ii) the p.Glu227Gln/p.Glu227Gln homodimer is as active as the wild-type AADC since the alteration occurs at the surface and does not change the chemical nature of the amino acid, and iii) the p.Glu227Gln/p.Arg347Gln heterodimer has a catalytic efficiency 75% that of the wild-type since only one of the two active sites is compromised, thus demonstrating a positive complementation. By this approach, the molecular basis for the mild presentation of the disease is provided, and the experience made can also be useful for personalized therapeutic decisions in other mild AADC deficiency patients. Interestingly, in the last few years, many previously undiagnosed or misdiagnosed patients have been identified as mild cases of AADC deficiency, expanding the phenotype of this neurotransmitter disease.
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Affiliation(s)
- Giovanni Bisello
- Department of Neuroscience, Biomedicine and Movement Sciences, Section of Biochemistry, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy
| | - Christiaan G.J. Saris
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands
| | - Rossella Franchini
- Department of Neuroscience, Biomedicine and Movement Sciences, Section of Biochemistry, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy
| | - Marcel M. Verbeek
- Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands
- Translational Metabolic Laboratory, Department of Human Gentics, Radboud University Medical Centre, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands
| | - Michel A.A.P. Willemsen
- Department of Pediatric Neurology, Radboud University Medical Centre, Geert Grooteplein 10, 6525 GA Nijmegen, the Netherlands
| | - Massimiliano Perduca
- Department of Biotechnology, University of Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Mariarita Bertoldi
- Department of Neuroscience, Biomedicine and Movement Sciences, Section of Biochemistry, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy
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Bisello G, Rossignoli G, Choi S, Phillips RS, Bertoldi M. Active site serine-193 modulates activity of human aromatic amino acid decarboxylase. Biochem Biophys Res Commun 2023; 679:6-14. [PMID: 37651872 DOI: 10.1016/j.bbrc.2023.08.049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 08/08/2023] [Accepted: 08/22/2023] [Indexed: 09/02/2023]
Abstract
Aromatic amino acid decarboxylase is a pyridoxal 5'-phosphate-dependent enzyme responsible for the synthesis of the neurotransmitters, dopamine and serotonin. Here, by a combination of bioinformatic predictions and analyses, phosphorylation assays, spectroscopic investigations and activity measurements, we determined that Ser-193, a conserved residue located at the active site, can be phosphorylated, increasing catalytic efficiency. In order to determine the molecular basis for this functional improvement, we determined the structural and kinetic properties of the site-directed variants S193A, S193D and S193E. While S193A retains 27% of the catalytic efficiency of wild-type, the two acidic side chain variants are impaired in catalysis with efficiencies of about 0.15% with respect to the wild-type. Thus, even if located at the active site, Ser-193 is not essential for enzyme activity. We advance the idea that this residue is fundamental for the correct architecture of the active site in terms of network of interactions triggering catalysis. This role has been compared with the properties of the Ser-194 of the highly homologous enzyme histidine decarboxylase whose catalytic loop is visible in the spatial structure, allowing us to propose the validation for the effect of the phosphorylation. The effect could be interesting for AADC deficiency, a rare monogenic disease, whose broad clinical phenotype could be also related to post translational AADC modifications.
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Affiliation(s)
- Giovanni Bisello
- Section of Biochemistry, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie, 8, Verona, Italy
| | - Giada Rossignoli
- Section of Biochemistry, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie, 8, Verona, Italy
| | - Sarah Choi
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, 30602, USA
| | - Robert S Phillips
- Department of Chemistry, University of Georgia, Athens, GA, 30602, USA; Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, 30602, USA.
| | - Mariarita Bertoldi
- Section of Biochemistry, Department of Neuroscience, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie, 8, Verona, Italy.
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Darbyshire AL, Wolthers KR. Expanding the β-substitution reactions of serine synthase through mutagenesis of aromatic active site residues. Arch Biochem Biophys 2023; 746:109727. [PMID: 37625767 DOI: 10.1016/j.abb.2023.109727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 08/21/2023] [Accepted: 08/22/2023] [Indexed: 08/27/2023]
Abstract
The Gram-negative bacterium, Fusobacterium nucleatum, possesses a fold II type pyridoxal 5'-phosphate-dependent enzyme that catalyzes the reversible β-replacement of l-cysteine and l-serine, generating H2S and H2O, respectively. This enzyme, termed serine synthase (FN1055), contains an active site Asp232 that serves as a general base in the activation of a water molecule for nucleophilic attack of the ⍺-aminoacrylate intermediate. A network of hydrophobic residues surrounding Asp232 are key to catalysis as they increase the basicity of the side chain. However, these residues severely restrict the range of nucleophilic substrates that can react with the ⍺-aminoacrylate, making the enzyme an ineffective biocatalyst for noncanonical amino acid biosynthesis. Herein, we systematically substituted four aromatic active residues (Trp99, Phe125, Phe148 and Phe234) to an alanine to determine their catalytic importance in serine/cysteine synthase reactions and if their substitution could broaden the scope of nucleophiles that could react with the ⍺-aminoacrylate intermediate. All four single site mutants W99A, F125A, F148A, and F234A could form the ⍺-aminoacrylate intermediate upon reaction with either l-cysteine or l-serine; however, the rate constant associated with the elimination of the β-hydroxyl group from l-serine was 150 to 200-fold lower in the F125A and F148A variants. Substitution of Phe125 and Phe148, situated ∼3-4 Å from the general base, also abolished the serine synthase reaction due to their inability to activate a water molecule for nucleophilic attack of the ⍺-aminoacrylate. Overall, the mutational studies indicate that the clustering of aromatic residues disproportionately benefits the serine synthase reaction as they increase the binding affinity for l-cysteine, decrease the binding of the product, l-serine, and promote the activation of a water molecule. Notably, the aminoacrylate species present in F125A and F148A was able to react with thiophenol, signifying that serine synthase has biocatalytic potential in the synthesis of noncanonical amino acids.
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Affiliation(s)
| | - Kirsten R Wolthers
- Department of Chemistry, University of British Columbia, Okanagan Campus, 3247 University Way, Kelowna, Canada.
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Babor J, Tramonti A, Nardella C, Deutschbauer A, Contestabile R, de Crécy-Lagard V. 4'-Deoxypyridoxine disrupts vitamin B 6 homeostasis in Escherichia coli K12 through combined inhibition of cumulative B 6 uptake and PLP-dependent enzyme activity. Microbiology (Reading) 2023; 169. [PMID: 37040165 DOI: 10.1099/mic.0.001319] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
Abstract
Pyridoxal 5'-phosphate (PLP) is the active form of vitamin B6 and a cofactor for many essential metabolic processes such as amino acid biosynthesis and one carbon metabolism. 4'-deoxypyridoxine (4dPN) is a long known B6 antimetabolite but its mechanism of action was not totally clear. By exploring different conditions in which PLP metabolism is affected in the model organism Escherichia coli K12, we showed that 4dPN cannot be used as a source of vitamin B6 as previously claimed and that it is toxic in several conditions where vitamin B6 homeostasis is affected, such as in a B6 auxotroph or in a mutant lacking the recently discovered PLP homeostasis gene, yggS. In addition, we found that 4dPN sensitivity is likely the result of multiple modes of toxicity, including inhibition of PLP-dependent enzyme activity by 4'-deoxypyridoxine phosphate (4dPNP) and inhibition of cumulative pyridoxine (PN) uptake. These toxicities are largely dependent on the phosphorylation of 4dPN by pyridoxal kinase (PdxK).
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Affiliation(s)
- Jill Babor
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
| | - Angela Tramonti
- Istituto di Biologia e Patologia Molecolari, Consiglio Nazionale delle Ricerche, Roma, Italy
- Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche, Sapienza Università di Roma, Rome, Italy
| | - Caterina Nardella
- Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche, Sapienza Università di Roma, Rome, Italy
| | - Adam Deutschbauer
- Environmental Genomics and Systems Biology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 74720, USA
| | - Roberto Contestabile
- Istituto Pasteur Italia - Fondazione Cenci Bolognetti, Dipartimento di Scienze Biochimiche, Sapienza Università di Roma, Rome, Italy
| | - Valérie de Crécy-Lagard
- Department of Microbiology and Cell Science, University of Florida, Gainesville, FL 32611, USA
- University of Florida Genetics Institute, Gainesville, FL 32610, USA
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Ding X, Wen Y, Ma X, Zhang Y, Cheng Y, Liu Z, Hu W, Xia Y. Pyridoxal 5'-phosphate alleviates prenatal pyridaben exposure-induced anxiety-like behaviors in offspring. Environ Sci Ecotechnol 2023; 13:100224. [PMID: 36437888 PMCID: PMC9691908 DOI: 10.1016/j.ese.2022.100224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 06/16/2023]
Abstract
Pyridaben (PY) is a widely used organochlorine acaricide, which can be detected in the peripheral blood of pregnant women. Available evidence suggests that PY has reproductive toxicity. However, it remains uncertain whether prenatal PY exposure impacts neurobehavioral development in offspring. Here, we administered PY to pregnant mice at a dose of 0.5 and 5 mg kg-1 day-1 via gavage and observed anxiety-like behaviors in PY offspring aged five weeks. We then integrated the metabolome and transcriptome of the offspring's brain to explore the underlying mechanism. Metabolome data indicated that the vitamin B6 metabolism pathway was significantly affected, and the pyridoxal 5'-phosphate (PLP) concentration and the active form of vitamin B6 was significantly reduced. Moreover, the transcriptome data showed that both PLP generation-related Pdxk and anxiety-related Gad1 were significantly down-regulated. Meanwhile, there was a decreasing trend in the concentration of GABA in the hippocampal DG region. Next, we supplemented PLP at a dose of 20 mg kg-1 day-1 to the PY offspring via intraperitoneal injection at three weeks. We found up-regulated expression of Pdxk and Gad1 and restored anxiety-like behaviors. This study suggests that prenatal exposure to PY can disrupt vitamin B6 metabolism, reduce the concentration of PLP, down-regulate the expression levels of Pdxk and Gad1, inhibit the production of GABA, and ultimately lead to anxiety-like behaviors in offspring.
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Affiliation(s)
- Xingwang Ding
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
| | - Ya Wen
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
- Department of Chronic Non-Communicable Disease Control, Wuxi Liangxi District Center for Disease Control and Prevention, Wuxi, 214011, China
| | - Xuan Ma
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
| | - Yuepei Zhang
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
| | - Yuting Cheng
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
| | - Zhaofeng Liu
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
| | - Weiyue Hu
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
- Department of Nutrition and Food Safety, School of Public Health, Nanjing Medical University, Nanjing, 211166, China
| | - Yankai Xia
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
- Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, 101 Longmian Avenue, Jiangning District, Nanjing, 211166, China
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Ma C, Chen Q, Mitchell DC, Na M, Tucker KL, Gao X. Application of the deep learning algorithm in nutrition research - using serum pyridoxal 5'-phosphate as an example. Nutr J 2022; 21:38. [PMID: 35689265 PMCID: PMC9185886 DOI: 10.1186/s12937-022-00793-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 05/31/2022] [Indexed: 01/21/2023] Open
Abstract
Background Multivariable linear regression (MLR) models were previously used to predict serum pyridoxal 5′-phosphate (PLP) concentration, the active coenzyme form of vitamin B6, but with low predictability. We developed a deep learning algorithm (DLA) to predict serum PLP based on dietary intake, dietary supplements, and other potential predictors. Methods This cross-sectional analysis included 3778 participants aged ≥20 years in the National Health and Nutrition Examination Survey (NHANES) 2007-2010, with completed information on studied variables. Dietary intake and supplement use were assessed with two 24-hour dietary recalls. We included potential predictors for serum PLP concentration in the models, including dietary intake and supplement use, sociodemographic variables (age, sex, race-ethnicity, income, and education), lifestyle variables (smoking status and physical activity level), body mass index, medication use, blood pressure, blood lipids, glucose, and C-reactive protein. We used a 4-hidden-layer deep neural network to predict PLP concentration, with 3401 (90%) participants for training and 377 (10%) participants for test using random sampling. We obtained outputs after sending the features of the training set and conducting forward propagation. We then constructed a loss function based on the distances between outputs and labels and optimized it to find good parameters to fit the training set. We also developed a prediction model using MLR. Results After training for 105 steps with the Adam optimization method, the highest R2 was 0.47 for the DLA and 0.18 for the MLR model in the test dataset. Similar results were observed in the sensitivity analyses after we excluded supplement-users or included only variables identified by stepwise regression models. Conclusions DLA achieved superior performance in predicting serum PLP concentration, relative to the traditional MLR model, using a nationally representative sample. As preliminary data analyses, the current study shed light on the use of DLA to understand a modifiable lifestyle factor. Supplementary Information The online version contains supplementary material available at 10.1186/s12937-022-00793-x.
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Affiliation(s)
- Chaoran Ma
- Channing Division of Network Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA
| | - Qipin Chen
- Department of Mathematics, The Pennsylvania State University, University Park, State College, PA, USA
| | - Diane C Mitchell
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, State College, PA, USA
| | - Muzi Na
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, State College, PA, USA
| | - Katherine L Tucker
- Department of Biomedical & Nutritional Sciences, The University of Massachusetts at Lowell, Lowell, MA, USA
| | - Xiang Gao
- Department of Nutrition and Food Hygiene, School of Public Health, Fudan University, 130 Dongan Rd, Shanghai, China.
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Kuznetsova AA, Faleev NG, Morozova EA, Anufrieva NV, Gogoleva OI, Tsvetikova MA, Fedorova OS, Demidkina TV, Kuznetsov NA. Analyses of pre-steady-state kinetics and isotope effects of the γ-elimination reaction catalyzed by Citrobacter freundii methionine γ-lyase. Biochimie 2022; 201:157-167. [PMID: 35691533 DOI: 10.1016/j.biochi.2022.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/18/2022] [Accepted: 06/06/2022] [Indexed: 11/29/2022]
Abstract
Methionine γ-lyase (MGL) is a pyridoxal 5'-phosphate-dependent enzyme catalyzing γ-elimination in l-methionine. Pyridoxal 5'-phosphate-dependent enzymes have unique spectral properties that allow to monitor sequential formation and decomposition of various intermediates via the detection of absorbance changes. The kinetic mechanism of the γ-elimination reaction catalyzed by Citrobacter freundii MGL was elucidated here by fast stopped-flow kinetic analysis. Single-wavelength detection of characteristic absorbance changes enabled us to compare transformations of intermediates in the course of the reaction with different substrates. The influence of various γ-substituents in the substrate on the formation of key intermediates was estimated. Kinetic isotope effects of α- and β-protons were determined using deuterium-substituted l-methionine. Contributions of amino acid residues Tyr113 and Tyr58 located in the active site on the formation and decomposition of reaction intermediates were identified too. α-Aminocrotonate formation is the rate-limiting step of the enzymatic γ-elimination reaction. Kinetic isotope effects strongly support concerted reaction mechanisms of transformation between an external aldimine and a ketimine intermediate as well as a ketimine intermediate and an unsaturated ketimine.
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Affiliation(s)
- Aleksandra A Kuznetsova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Nicolai G Faleev
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Elena A Morozova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Natalya V Anufrieva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Olga I Gogoleva
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Marina A Tsvetikova
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Olga S Fedorova
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090, Russia
| | - Tatyana V Demidkina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia.
| | - Nikita A Kuznetsov
- Institute of Chemical Biology and Fundamental Medicine, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090, Russia.
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Whyte MP, Zhang F, Wenkert D, Mack KE, Bijanki VN, Ericson KL, Coburn SP. Hypophosphatasia: Vitamin B 6 status of affected children and adults. Bone 2022; 154:116204. [PMID: 34547524 DOI: 10.1016/j.bone.2021.116204] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 09/09/2021] [Accepted: 09/14/2021] [Indexed: 12/20/2022]
Abstract
Hypophosphatasia (HPP) is the heritable dento-osseous disease caused by loss-of-function mutation(s) of the gene ALPL that encodes the tissue-nonspecific isoenzyme of alkaline phosphatase (TNSALP). TNSALP is a cell-surface homodimeric phosphomonoester phosphohydrolase expressed in healthy people especially in the skeleton, liver, kidneys, and developing teeth. In HPP, diminished TNSALP activity leads to extracellular accumulation of its natural substrates including inorganic pyrophosphate (PPi), an inhibitor of mineralization, and pyridoxal 5'-phosphate (PLP), the principal circulating form of vitamin B6 (B6). Autosomal dominant and autosomal recessive inheritance involving >450 usually missense defects scattered throughout ALPL largely explains the remarkably broad-ranging severity of this inborn-error-of-metabolism. In 1985 when we identified elevated plasma PLP as a biochemical hallmark of HPP, all 14 investigated affected children and adults had markedly increased PLP levels. However, pyridoxal (PL), the dephosphorylated form of PLP that enters cells to cofactor many enzymatic reactions, was not low but often inexplicably elevated. Levels of pyridoxic acid (PA), the B6 degradation product quantified to assess B6 sufficiency, were unremarkable. Canonical signs or symptoms of B6 deficiency or toxicity were absent. B6-dependent seizures in infants with life-threatening HPP were later explained by their profound deficiency of TNSALP activity blocking PLP dephosphorylation to PL and diminishing gamma-aminobutyric acid synthesis in the brain. Now, there is speculation that altered B6 metabolism causes further clinical complications in HPP. Herein, we assessed the plasma PL and PA levels accompanying previously reported elevated plasma PLP concentrations in 150 children and adolescents with HPP. Their mean (SD) plasma PL level was nearly double the mean for our healthy pediatric controls: 66.7 (59.0) nM versus 37.1 (22.2) nM (P < 0.0001), respectively. Their PA levels were broader than our pediatric control range, but their mean value was normal; 40.2 (25.1) nM versus 39.3 (9.9) nM (P = 0.7793), respectively. In contrast, adults with HPP often had plasma PL and PA levels suggestive of dietary B6 insufficiency. We discuss why the B6 levels of our pediatric patients with HPP would not cause B6 toxicity or deficiency, whereas in affected adults dietary B6 insufficiency can develop.
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Affiliation(s)
- Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children - St. Louis, St. Louis, MO 63110, USA; Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, MO 63110, USA.
| | - Fan Zhang
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children - St. Louis, St. Louis, MO 63110, USA.
| | - Deborah Wenkert
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children - St. Louis, St. Louis, MO 63110, USA.
| | - Karen E Mack
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children - St. Louis, St. Louis, MO 63110, USA.
| | - Vinieth N Bijanki
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children - St. Louis, St. Louis, MO 63110, USA.
| | - Karen L Ericson
- Department of Chemistry, Purdue University Fort Wayne, Fort Wayne, IN 46805, USA.
| | - Stephen P Coburn
- Department of Chemistry, Purdue University Fort Wayne, Fort Wayne, IN 46805, USA.
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Kim H, Song D, Ngo HV, Jin G, Park C, Park JB, Lee BJ. Modulation of the clinically accessible gelation time using glucono-d-lactone and pyridoxal 5'-phosphate for long-acting alginate in situ forming gel injectable. Carbohydr Polym 2021; 272:118453. [PMID: 34420713 DOI: 10.1016/j.carbpol.2021.118453] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 07/12/2021] [Accepted: 07/14/2021] [Indexed: 10/20/2022]
Abstract
The purpose of this study was to design alginate in situ forming gel (ISFG) injectable with clinically acceptable gelation time and controlled release of hydrophobic drug. Milled or unmilled paliperidone palmitate (PPP) was used. The gelation time was controlled by varying the ratios of glucono-d-lactone (GDL) and pyridoxal 5'-phosphate (PLP) in prefilled alginate solution mixtures (ASMs) containing PPP, CaCO3, GDL and PLP for clinically acceptable injectability. However, the gelation time was varied by the alginate type (M/G ratio), storage condition, and drug solubilizers. This ISFG exhibited 32.15 kPa of the maximal compressive stress without causing pain and stiffness. The ISFG containing conically milled PPP released PPP in a controlled manner without exhibiting any initial burst release for 4 weeks. The current alginate ISFG injectable using new combination of PLP and GDL could be used to deliver long-acting injectable drugs.
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Affiliation(s)
- Hyungtaek Kim
- College of Pharmacy, Ajou University, Suwon 16499, Republic of Korea
| | - Dahee Song
- College of Pharmacy, Ajou University, Suwon 16499, Republic of Korea
| | - Hai V Ngo
- College of Pharmacy, Ajou University, Suwon 16499, Republic of Korea
| | - Gang Jin
- College of Pharmacy, Ajou University, Suwon 16499, Republic of Korea
| | - Chulhun Park
- Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, Alberta, Canada
| | - Jun-Bom Park
- College of Pharmacy, Sahmyook University, Seoul 01795, Republic of Korea
| | - Beom-Jin Lee
- College of Pharmacy, Ajou University, Suwon 16499, Republic of Korea; Institute of Pharmaceutical Science and Technology, Ajou University, Suwon 16499, Republic of Korea.
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Longo C, Montioli R, Bisello G, Palazzi L, Mastrangelo M, Brennenstuhl H, de Laureto PP, Opladen T, Leuzzi V, Bertoldi M. Compound heterozygosis in AADC deficiency: A complex phenotype dissected through comparison among heterodimeric and homodimeric AADC proteins. Mol Genet Metab 2021; 134:147-155. [PMID: 34479793 DOI: 10.1016/j.ymgme.2021.08.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 08/25/2021] [Accepted: 08/25/2021] [Indexed: 10/20/2022]
Abstract
Compound heterozygosis is the most diffuse and hardly to tackle condition in aromatic amino acid decarboxylase (AADC) deficiency, a genetic disease leading to severe neurological impairment. Here, by using an appropriate vector, we succeeded in obtaining high yields of AADC protein and characterizing two new heterodimers, T69M/S147R and C281W/M362T, detected in two AADC deficiency patients. We performed an extensive biochemical characterization of the heterodimeric recombinant proteins and of the related homodimers, by a combination of dichroic and fluorescence spectroscopy and activity assays together with bioinformatic analyses. We found that T69M/S147R exhibits negative complementation in terms of activity but it is more stable than the average of the homodimeric counterparts. The heterodimer C281W/M362T retains a nearly good catalytic efficiency, whereas M362T homodimer is less affected and C281W homodimer is recovered as insoluble. These results, which are consistent with the related phenotypes, and the data emerging from previous studies, suggest that the severity of AADC deficiency is not directly explained by positive or negative complementation phenomena, but rather depends on: i) the integrity of one or both active sites; ii) the structural and functional properties of the entire pool of AADC proteins expressed. Overall, this integrated and cross-sectional approach enables proper characterization and depicts the functional result of subunit interactions in the dimeric structure and will help to elucidate the physio-pathological mechanisms in AADC deficiency.
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Affiliation(s)
- Carmen Longo
- Department of Neuroscience, Biomedicine and Movement Sciences, Section of Biological Chemistry, Strada Le Grazie 8, 37134 Verona, Italy
| | - Riccardo Montioli
- Department of Neuroscience, Biomedicine and Movement Sciences, Section of Biological Chemistry, Strada Le Grazie 8, 37134 Verona, Italy
| | - Giovanni Bisello
- Department of Neuroscience, Biomedicine and Movement Sciences, Section of Biological Chemistry, Strada Le Grazie 8, 37134 Verona, Italy
| | - Luana Palazzi
- Department of Pharmaceutical and Pharmacological Sciences, CRIBI Biotechnology Center, University of Padua, Padua, Italy
| | - Mario Mastrangelo
- Unit of Child Neurology and Psychiatry Unit, Department of Human Neuroscience, Sapienza University of Rome, Italy
| | - Heiko Brennenstuhl
- University Children's Hospital Heidelberg, Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Heidelberg, Germany
| | - Patrizia Polverino de Laureto
- Department of Pharmaceutical and Pharmacological Sciences, CRIBI Biotechnology Center, University of Padua, Padua, Italy
| | - Thomas Opladen
- University Children's Hospital Heidelberg, Department of General Pediatrics, Division of Neuropediatrics and Metabolic Medicine, Heidelberg, Germany
| | - Vincenzo Leuzzi
- Unit of Child Neurology and Psychiatry Unit, Department of Human Neuroscience, Sapienza University of Rome, Italy
| | - Mariarita Bertoldi
- Department of Neuroscience, Biomedicine and Movement Sciences, Section of Biological Chemistry, Strada Le Grazie 8, 37134 Verona, Italy.
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Badawy AA. Multiple roles of haem in cystathionine β-synthase activity: implications for hemin and other therapies of acute hepatic porphyria. Biosci Rep 2021; 41:BSR20210935. [PMID: 34251022 DOI: 10.1042/BSR20210935] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 07/08/2021] [Accepted: 07/09/2021] [Indexed: 12/27/2022] Open
Abstract
The role of haem in the activity of cystathionine β-synthase (CBS) is reviewed and a hypothesis postulating multiple effects of haem on enzyme activity under conditions of haem excess or deficiency is proposed, with implications for some therapies of acute hepatic porphyrias. CBS utilises both haem and pyridoxal 5′-phosphate (PLP) as cofactors. Although haem does not participate directly in the catalytic process, it is vital for PLP binding to the enzyme and potentially also for CBS stability. Haem deficiency can therefore undermine CBS activity by impairing PLP binding and facilitating CBS degradation. Excess haem can also impair CBS activity by inhibiting it via CO resulting from haem induction of haem oxygenase 1 (HO 1), and by induction of a functional vitamin B6 deficiency following activation of hepatic tryptophan 2,3-dioxygenase (TDO) and subsequent utilisation of PLP by enhanced kynurenine aminotransferase (KAT) and kynureninase (Kynase) activities. CBS inhibition results in accumulation of the cardiovascular risk factor homocysteine (Hcy) and evidence is emerging for plasma Hcy elevation in patients with acute hepatic porphyrias. Decreased CBS activity may also induce a proinflammatory state, inhibit expression of haem oxygenase and activate the extrahepatic kynurenine pathway (KP) thereby further contributing to the Hcy elevation. The hypothesis predicts likely changes in CBS activity and plasma Hcy levels in untreated hepatic porphyria patients and in those receiving hemin or certain gene-based therapies. In the present review, these aspects are discussed, means of testing the hypothesis in preclinical experimental settings and porphyric patients are suggested and potential nutritional and other therapies are proposed.
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Kishnani PS, Del Angel G, Zhou S, Rush ET. Investigation of ALPL variant states and clinical outcomes: An analysis of adults and adolescents with hypophosphatasia treated with asfotase alfa. Mol Genet Metab 2021; 133:113-121. [PMID: 33814268 DOI: 10.1016/j.ymgme.2021.03.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 02/03/2021] [Accepted: 03/14/2021] [Indexed: 12/22/2022]
Abstract
BACKGROUND Hypophosphatasia (HPP), a rare metabolic disease, can be inherited in an autosomal recessive (biallelic) or an autosomal dominant (monoallelic) manner. Most of the severe, early-onset, frequently lethal HPP in infants is acquired through recessive inheritance; less severe, later-onset, typically nonlethal HPP phenotypes are acquired through either dominant or recessive inheritance. HPP's variable clinical presentation arises from >400 identified ALPL pathogenic variants with likely variable penetrance, especially with autosomal dominant inheritance. This post hoc analysis investigated the relationship between ALPL variant state (biallelic and monoallelic) and clinical outcomes with asfotase alfa in HPP. METHODS Data were pooled from two phase 2, randomized, open-label studies in adolescents and adults with HPP; one study evaluated the efficacy and safety of different doses of asfotase alfa (n = 25), and the other assessed the pharmacodynamics and safety of asfotase alfa (n = 19). Patients were grouped by ALPL variant state (biallelic or monoallelic). Available data from both studies included ALPL pathogenic variant state, Baseline characteristics, HPP-specific medical history, and Baseline TNSALP substrate levels (inorganic pyrophosphate [PPi] and pyridoxal 5'-phosphate [PLP]) concentrations). Clinical outcomes over 5 years of treatment were available from only the efficacy and safety study. RESULTS In total, 44 patients with known variant status were included in the pooled analysis (biallelic, n = 30; monoallelic, n = 14). The most common pathogenic variant was c.571G > A (p.Glu191Lys) in biallelic patients (allele frequency: 19/60) and c.1133A > T (p.Asp378Val) in monoallelic patients (allele frequency: 7/28). Median (min, max) Baseline PPi concentrations were significantly higher in patients with a biallelic vs monoallelic variant state (5.3 [2.2, 12.1] vs 4.3 [3.5, 7.4] μM; P = 0.0113), as were Baseline PLP concentrations (221.4 [62.4, 1590.0] vs 75.1 [28.8, 577.0] ng/mL; P= 0.0022). HPP-specific medical history was generally similar between biallelic and monoallelic patients in terms of incidence and type of manifestations; notable exceptions included fractures, which were more common among monoallelic patients, and delayed walking and bone deformities such as abnormally shaped chest and head and bowing of arms or legs, which were more common among biallelic patients. Data from the efficacy and safety study (n = 19) showed that median PPi and PLP concentrations were normalized over 5 years of treatment in patients with both variant states. Median % predicted distance walked on the 6-Minute Walk Test remained within the normal range for monoallelic patients over 4 years of treatment, and improved from below normal (<84%) to normal in biallelic patients. CONCLUSIONS Although patients with biallelic variants had significantly higher Baseline PPi and PLP levels than monoallelic variants, both groups generally showed similar pretreatment Baseline clinical characteristics. Treatment with asfotase alfa for up to 5 years normalized TNSALP substrate concentrations and improved functional outcomes, with no clear differences between biallelic and monoallelic variant states. This study suggests that patients with HPP have significant disease burden, regardless of ALPL variant state.
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Affiliation(s)
- Priya S Kishnani
- Department of Pediatrics, Duke University Medical Center, 2351 Erwin Road, Durham, NC, USA.
| | | | - Shanggen Zhou
- Covance, Inc., 206 Carnegie Center Dr, Princeton, NJ, USA.
| | - Eric T Rush
- Children's Mercy Hospital Kansas City, 2401 Gillham Rd, Kansas City, MO, USA; University of Missouri-Kansas City School of Medicine, Kansas City, MO, USA; University of Kansas School of Medicine, Kansas City, KS, USA.
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13
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Shih IT, Yi YC, Ng IS. Plasmid-Free System and Modular Design for Efficient 5-Aminolevulinic Acid Production by Engineered Escherichia coli. Appl Biochem Biotechnol 2021; 193:2858-2871. [PMID: 33860878 DOI: 10.1007/s12010-021-03571-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Accepted: 04/08/2021] [Indexed: 11/30/2022]
Abstract
5-Aminolevulinic acid (ALA) is an essential intermediate for many organisms and has been considered for the applications of medical especially in photodynamic therapy of cancer recently. However, ALA production via chemical approach is complicated; hence, microbial manufacturing has received more attentions. In this study, a modular design to simultaneously express ALA synthase from Rhodobacter sphaeroides (RshemA), a non-specific ALA exporter (RhtA), and chaperones was first developed and discussed. The ALA production was significantly increased by coexpressing RhtA and RshemA. Besides, ALA was enhanced by the cofactor pyridoxal phosphate (PLP) which was supplied by expressing genes of pdxK and pdxY or direct addition. However, inclusion bodies of RshemA served as an obstacle; thus, chaperones DnaK and GroELS were introduced to reform the conformation of proteins and successfully improved ALA production. Finally, a plasmid-free strain RrGI, as the robust chassis, was established and a 6.23-fold enhancement on ALA biosynthesis and led to 7.47 g/L titer and 0.588 g/L/h productivity under the optimal cultural condition.
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Affiliation(s)
- I-Tai Shih
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan
| | - Ying-Chen Yi
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan, 70101, Taiwan.
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Richts B, Commichau FM. Underground metabolism facilitates the evolution of novel pathways for vitamin B6 biosynthesis. Appl Microbiol Biotechnol 2021; 105:2297-2305. [PMID: 33665688 PMCID: PMC7954711 DOI: 10.1007/s00253-021-11199-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 02/15/2021] [Accepted: 02/24/2021] [Indexed: 11/29/2022]
Abstract
Abstract The term vitamin B6 is a designation for the vitamers pyridoxal, pyridoxamine, pyridoxine and the respective phosphate esters pyridoxal-5′-phosphate (PLP), pyridoxamine-5′-phosphate and pyridoxine-5′-phosphate. Animals and humans are unable to synthesise vitamin B6. These organisms have to take up vitamin B6 with their diet. Therefore, vitamin B6 is of commercial interest as a food additive and for applications in the pharmaceutical industry. As yet, two naturally occurring routes for de novo synthesis of PLP are known. Both routes have been genetically engineered to obtain bacteria overproducing vitamin B6. Still, major genetic engineering efforts using the existing pathways are required for developing fermentation processes that could outcompete the chemical synthesis of vitamin B6. Recent suppressor screens using mutants of the Gram-negative and Gram-positive model bacteria Escherichia coli and Bacillus subtilis, respectively, carrying mutations in the native pathways or heterologous genes uncovered novel routes for PLP biosynthesis. These pathways consist of promiscuous enzymes and enzymes that are already involved in vitamin B6 biosynthesis. Thus, E. coli and B. subtilis contain multiple promiscuous enzymes causing a so-called underground metabolism allowing the bacteria to bypass disrupted vitamin B6 biosynthetic pathways. The suppressor screens also show the genomic plasticity of the bacteria to suppress a genetic lesion. We discuss the potential of the serendipitous pathways to serve as a starting point for the development of bacteria overproducing vitamin B6. Key points • Known vitamin B6 routes have been genetically engineered. • Underground metabolism facilitates the emergence of novel vitamin B6 biosynthetic pathways. • These pathways may be suitable to engineer bacteria overproducing vitamin B6.
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Affiliation(s)
- Björn Richts
- Department of General Microbiology, Institute for Microbiology and Genetics, University of Goettingen, Grisebachstrasse 8, 37077, Göttingen, Germany
| | - Fabian M Commichau
- FG Synthetic Microbiology, Institute for Biotechnology, BTU Cottbus-Senftenberg, Universitätsplatz 1, 01968, Senftenberg, Germany.
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15
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Jandl NM, Schmidt T, Rolvien T, Stürznickel J, Chrysostomou K, von Vopelius E, Volk AE, Schinke T, Kubisch C, Amling M, Barvencik F. Genotype-Phenotype Associations in 72 Adults with Suspected ALPL-Associated Hypophosphatasia. Calcif Tissue Int 2021; 108:288-301. [PMID: 33191482 PMCID: PMC7881968 DOI: 10.1007/s00223-020-00771-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 10/12/2020] [Indexed: 12/11/2022]
Abstract
Hypophosphatasia (HPP) is a rare inborn error of metabolism due to a decreased activity of tissue nonspecific alkaline phosphatase (TNSALP). As the onset and severity of HPP are heterogenous, it can be challenging to determine the pathogenicity of detected rare ALPL variants in symptomatic patients. We aimed to characterize patients with rare ALPL variants to propose which patients can be diagnosed with adult HPP. We included 72 patients with (1) clinical symptoms of adult HPP or positive family history and (2) low TNSALP activity and/or high pyridoxal 5'-phosphate (PLP) levels, who underwent ALPL gene sequencing. The patients were analyzed and divided into three groups depending on ALPL variant pathogenicity according to the classification of the American College of Medical Genetics and Genomics (ACMG). Reported pathogenic (n = 34 patients), rare (n = 17) and common (n = 21) ALPL variants only were found. Muscular complaints were the most frequent symptoms (> 80%), followed by bone affection (> 50%). Tooth involvement was significantly more common in patients with pathogenic or rare ALPL variants. Seven rare variants could be classified as likely pathogenic (ACMG class 4) of which five have not yet been described. Inconclusive genetic findings and less specific symptoms make diagnosis difficult in cases where adult HPP is not obvious. As not every pathogenic or rare ALPL variant leads to a manifestation of HPP, only patients with bone complications and at least one additional complication concerning teeth, muscle, central nervous and mental system, repeated low TNSALP activity and high PLP levels should be diagnosed as adult HPP if rare ALPL gene variants of ACMG class 4 or higher support the diagnosis.
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Affiliation(s)
- Nico Maximilian Jandl
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529, Hamburg, Germany
- Department of Orthopedics, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Tobias Schmidt
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529, Hamburg, Germany
| | - Tim Rolvien
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529, Hamburg, Germany
- Department of Orthopedics, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Julian Stürznickel
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529, Hamburg, Germany
| | - Konstantin Chrysostomou
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529, Hamburg, Germany
| | - Emil von Vopelius
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529, Hamburg, Germany
- Department of Orthopedics, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Alexander E Volk
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Thorsten Schinke
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529, Hamburg, Germany
| | - Christian Kubisch
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Michael Amling
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529, Hamburg, Germany
| | - Florian Barvencik
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 59, 22529, Hamburg, Germany.
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Han YH, Kim HJ, Choi TR, Song HS, Lee SM, Park SL, Lee HS, Cho JY, Bhatia SK, Gurav R, Park K, Yang YH. Improvement of cadaverine production in whole cell system with baker's yeast for cofactor regeneration. Bioprocess Biosyst Eng 2021; 44:891-9. [PMID: 33486578 DOI: 10.1007/s00449-020-02497-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 12/09/2020] [Indexed: 01/13/2023]
Abstract
Cadaverine, 1,5-diaminopentane, is one of the most promising chemicals for biobased-polyamide production and it has been successfully produced up to molar concentration. Pyridoxal 5'-phosphate (PLP) is a critical cofactor for inducible lysine decarboxylase (CadA) and is required up to micromolar concentration level. Previously the regeneration of PLP in cadaverine bioconversion has been studied and salvage pathway pyridoxal kinase (PdxY) was successfully introduced; however, this system also required a continuous supply of adenosine 5'-triphosphate (ATP) for PLP regeneration from pyridoxal (PL) which add in cost. Herein, to improve the process further a method of ATP regeneration was established by applying baker's yeast with jhAY strain harboring CadA and PdxY, and demonstrated that providing a moderate amount of adenosine 5'-triphosphate (ATP) with the simple addition of baker's yeast could increase cadaverine production dramatically. After optimization of reaction conditions, such as PL, adenosine 5'-diphosphate, MgCl2, and phosphate buffer, we able to achieve high production (1740 mM, 87% yield) from 2 M L-lysine. Moreover, this approach could give averaged 80.4% of cadaverine yield after three times reactions with baker's yeast and jhAY strain. It is expected that baker's yeast could be applied to other reactions requiring an ATP regeneration system.
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Ghatge MS, Al Mughram M, Omar AM, Safo MK. Inborn errors in the vitamin B6 salvage enzymes associated with neonatal epileptic encephalopathy and other pathologies. Biochimie 2021; 183:18-29. [PMID: 33421502 DOI: 10.1016/j.biochi.2020.12.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 12/28/2020] [Accepted: 12/30/2020] [Indexed: 12/28/2022]
Abstract
Pyridoxal 5'-phosphate (PLP), the active cofactor form of vitamin B6 is required by over 160 PLP-dependent (vitamin B6) enzymes serving diverse biological roles, such as carbohydrates, amino acids, hemes, and neurotransmitters metabolism. Three key enzymes, pyridoxal kinase (PL kinase), pyridoxine 5'-phosphate oxidase (PNPO), and phosphatases metabolize and supply PLP to PLP-dependent enzymes through the salvage pathway. In born errors in the salvage enzymes are known to cause inadequate levels of PLP in the cell, particularly in neuronal cells. The resulting PLP deficiency is known to cause or implicated in several pathologies, most notably seizures. One such disorder, PNPO-dependent neonatal epileptic encephalopathy (NEE) results from natural mutations in PNPO and leads to null or reduced enzymatic activity. NEE does not respond to conventional antiepileptic drugs but may respond to treatment with the B6 vitamers PLP and/or pyridoxine (PN). In born errors that lead to PLP deficiency in cells have also been reported in PL kinase, however, to date none has been associated with epilepsy or seizure. One such pathology is polyneuropathy that responds to PLP therapy. Phosphatase deficiency or hypophosphatasia disorder due to pathogenic mutations in alkaline phosphatase is known to cause seizures that respond to PN therapy. In this article, we review the biochemical features of in born errors pertaining to the salvage enzyme's deficiency that leads to NEE and other pathologies. We also present perspective on vitamin B6 treatment for these disorders, along with attempts to develop zebrafish model to study the NEE syndrome in vivo.
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Affiliation(s)
- Mohini S Ghatge
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Mohammed Al Mughram
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA
| | - Abdelsattar M Omar
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, King Abdulaziz University, Alsulaymanyah, Jeddah, 21589, Saudi Arabia; Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Al-Azhar University, Cairo, 11884, Egypt
| | - Martin K Safo
- Department of Medicinal Chemistry, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA; Institute for Structural Biology, Drug Discovery, and Development, School of Pharmacy, Virginia Commonwealth University, Richmond, VA, 23298, USA.
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Jungert A, Neuhäuser-Berthold M. Determinants of Vitamin B6 Status in Community-Dwelling Older Adults: A Longitudinal Study Over a Period of 18 Years. J Gerontol A Biol Sci Med Sci 2020; 75:374-379. [PMID: 30657862 DOI: 10.1093/gerona/glz010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Cross-sectional studies indicate an age-related decline in vitamin B6 status. Because longitudinal studies are lacking, the present study investigates the long-term association between age and vitamin B6 status in older adults by considering potential confounding factors. METHODS The study population consists of 249 women and 111 men aged ≥ 60 years, who had at least three follow-ups between 1996 and 2014 with complete data records on relevant parameters. Vitamin B6 status was assessed by serum pyridoxal 5'-phosphate (PLP) concentrations measured by high-performance liquid chromatography. Linear mixed models were used to analyze the influence of age, sex, body composition, supplements, diet, lifestyle, and serum creatinine on PLP concentrations. RESULTS At baseline, 37% of the subjects showed PLP concentrations < 30 nmol/L and more than half failed to meet the recommended dietary intake. Longitudinal analyses revealed that age, use of supplements and protein intake were positive determinants of PLP concentrations, whereas body fat showed a negative impact. No influence of sex, dietary vitamin B6 intake, lifestyle factors or serum creatinine on PLP concentrations was found. CONCLUSION The present study provides no evidence that in the course of aging PLP concentrations decline between 60 and 90 years. However, age-related changes in body composition, such as an increased ratio of fat mass to fat-free mass may negatively affect vitamin B6 status.
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Affiliation(s)
- Alexandra Jungert
- Institute of Nutritional Science, Justus Liebig University, Giessen, Germany
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Hussain S, Huang J, Zhu C, Zhu L, Cao X, Hussain S, Ashraf M, Khaskheli MA, Kong Y, Jin Q, Li X, Zhang J. Pyridoxal 5'-phosphate enhances the growth and morpho-physiological characteristics of rice cultivars by mitigating the ethylene accumulation under salinity stress. Plant Physiol Biochem 2020; 154:782-795. [PMID: 32680726 DOI: 10.1016/j.plaphy.2020.05.035] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Revised: 05/12/2020] [Accepted: 05/27/2020] [Indexed: 06/11/2023]
Abstract
Salinity-induced ethylene accumulation caused by high production of 1-aminocyclopropane-1-carboxylic acid (ACC) hinders rice plant growth and development. Nevertheless, ACC deaminase may alleviate salt stress and high ethylene production in rice cultivars under salinity stress. Pyridoxal 5'-phosphate (PLP), an ACC deaminase co-factor, could be a useful ACC inhibitor in plants; however, it has not been studied before. In the present study, the effects of PLP on the growth and morphophysiological characteristics of rice cultivars (Jinyuan 85 (JY85) and Nipponbare (NPBA) were investigated under salinity stress (control (CK), low salinity (LS), and high salinity (HS) in hydroponic conditions. The experiment was laid out in a completely randomized design (CRD) under factorial arrangement of treatments. The results showed that, compared with no PLP, exogenous application of PLP significantly inhibited ACC and ethylene production in the roots, leaves and panicles of both cultivars under salinity, and PLP was more effective at improving the physiological characteristics of both cultivars under salinity stress. Further, root morphophysiological traits and pollen viability were triggered in the PLP treatment compared to the no-PLP treatment under various salinity levels. ACC production inhibited by PLP was useful for improving the 1000-grain weight, grain yield per plant, and total plant biomass under the CK, LS and HS treatments in both rice cultivars. These results revealed that PLP, as an ACC deaminase cofactor, is a key tool for mitigating ethylene-induced effects under salinity stress and for enhancing the agronomic and morphophysiological traits of rice under saline conditions.
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Affiliation(s)
- Sajid Hussain
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, Zhejiang, China.
| | - Jing Huang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, Zhejiang, China.
| | - Chunquan Zhu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, Zhejiang, China.
| | - Lianfeng Zhu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, Zhejiang, China.
| | - Xiaochuang Cao
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, Zhejiang, China.
| | - Saddam Hussain
- Department of Agronomy, University of Agriculture Faisalabad, 38000, Punjab, Pakistan.
| | - Muhammad Ashraf
- Department of Soil Science, Bahauddin Zakariya University, Multan, Pakistan.
| | - Maqsood Ahmed Khaskheli
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, Zhejiang, China.
| | - Yali Kong
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, Zhejiang, China.
| | - Qianyu Jin
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, Zhejiang, China.
| | - Xiaopeng Li
- Institute of Soil Science, Chinese Academy of Science, Nanjing, 210008, Jiangsu, China.
| | - Junhua Zhang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou, 310006, Zhejiang, China.
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Whyte MP, Ma NS, Mumm S, Gottesman GS, McAlister WH, Nenninger AR, Bijanki VN, Ericson KL, Magnusson P. Persistent idiopathic hyperphosphatasemia from bone alkaline phosphatase in a healthy boy. Bone 2020; 138:115459. [PMID: 32474245 DOI: 10.1016/j.bone.2020.115459] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 05/26/2020] [Accepted: 05/26/2020] [Indexed: 11/19/2022]
Abstract
Alkaline phosphatase (ALP) in humans comprises a family of four cell-surface phosphomonoester phosphohydrolase isozymes. Three genes separately encode the "tissue-specific" ALPs whereas the fourth gene encodes ubiquitous homodimeric "tissue-nonspecific" ALP (TNSALP) richly expressed in bone, liver, kidney, and developing teeth. TNSALP monomers have five putative N-linked glycosylation sites where different post-translational modifications account for this isozyme's distinctive physicochemical properties in different organs. Three bone-derived TNSALP (BALP) isoforms (B/I, B1, and B2) are present in healthy serum, whereas a fourth BALP isoform (B1x) can circulate in chronic kidney disease. Herein, we report a healthy boy with persistent hyperphosphatasemia due to BALP levels two- to threefold higher than age-appropriate reference values. High-performance liquid chromatography, electrophoresis, heat inactivation, catalysis inhibition, and polyethylene glycol precipitation revealed increased serum B/I, B1, and B2 differing from patterns found in skeletal diseases. B/I was ~23-fold elevated. Absence of mental retardation and physical stigmata excluded Mabry syndrome, the ALP-anchoring disorder causing hyperphosphatasemia. Routine biochemical studies indicated intact mineral homeostasis. Serum N-terminal propeptide of type I procollagen (P1NP) level was normal, but C-terminal cross-linking telopeptide of type I collagen (CTX) level was elevated. However, radiological studies showed no evidence for a generalized skeletal disturbance. Circulating pyridoxal 5'-phosphate, a TNSALP natural substrate, was not low despite the laboratory hyperphosphatasemia, thereby suggesting BALP phosphohydrolase activity was not elevated endogenously. Mutation analysis of the ALPL gene encoding TNSALP revealed no defect. His non-consanguineous healthy parents had serum total ALP activity and BALP protein levels that were normal. Our patient's sporadic idiopathic hyperphosphatasemia could reflect altered post-translational modification together with increased expression and/or impaired degradation of BALP.
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Affiliation(s)
- Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children, St. Louis, MO 63110, USA; Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, MO 63110, USA.
| | - Nina S Ma
- Division of Endocrinology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
| | - Steven Mumm
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children, St. Louis, MO 63110, USA; Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, MO 63110, USA.
| | - Gary S Gottesman
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children, St. Louis, MO 63110, USA.
| | - William H McAlister
- Mallinckrodt Institute of Radiology, Washington University School of Medicine at St. Louis Children's Hospital, St. Louis, MO 63110, USA.
| | - Angela R Nenninger
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children, St. Louis, MO 63110, USA.
| | - Vinieth N Bijanki
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospitals for Children, St. Louis, MO 63110, USA.
| | - Karen L Ericson
- Department of Chemistry, Purdue University-Fort Wayne, Fort Wayne, IN 46805, USA.
| | - Per Magnusson
- Department of Clinical Chemistry and Department of Biomedical and Clinical Sciences, Linköping University, SE-58185 Linköping, Sweden.
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21
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Gamov GA, Meshkov AN, Zavalishin MN, Petrova MV, Khokhlova AY, Gashnikova AV, Sharnin VA. Binding of pyridoxal, pyridoxal 5'-phosphate and derived hydrazones to bovine serum albumin in aqueous solution. Spectrochim Acta A Mol Biomol Spectrosc 2020; 233:118165. [PMID: 32120288 DOI: 10.1016/j.saa.2020.118165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 02/10/2020] [Accepted: 02/16/2020] [Indexed: 06/10/2023]
Abstract
In the present paper, the kinetics of a reaction between bovine serum albumin (BSA) and pyridoxal, pyridoxal 5'-phosphate was studied, apparent rate constant of product formation and dissociation as well as binding constants were determined. Pyridoxal 5'-phosphate hydrazones of isonicotinic, picolinic, 2-furoic, thiophene-2-carboxylic, pyrazinoic acids binding to BSA was studied by spectrofluorimetry, stability constants of the associates were calculated from experimental data using maximal likelihood approach. The changes in the secondary structure of BSA induced by hydrazones addition were studied by IR spectroscopy. New freely available software for curve fitting was developed as a part of the software kit designed for the solution chemistry and used for a specific problem of this study, IR spectra processing.
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Affiliation(s)
- G A Gamov
- Research Institute of Thermodynamics and Kinetics of Chemical Processes, Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Sheremetevskii pr. 7, Russia.
| | | | - M N Zavalishin
- Research Institute of Thermodynamics and Kinetics of Chemical Processes, Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Sheremetevskii pr. 7, Russia
| | - M V Petrova
- Research Institute of Thermodynamics and Kinetics of Chemical Processes, Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Sheremetevskii pr. 7, Russia
| | - A Yu Khokhlova
- Research Institute of Thermodynamics and Kinetics of Chemical Processes, Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Sheremetevskii pr. 7, Russia
| | - A V Gashnikova
- Research Institute of Thermodynamics and Kinetics of Chemical Processes, Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Sheremetevskii pr. 7, Russia
| | - V A Sharnin
- Research Institute of Thermodynamics and Kinetics of Chemical Processes, Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Sheremetevskii pr. 7, Russia
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22
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Ito T, Matsuoka M, Goto M, Watanabe S, Mizobuchi T, Matsushita K, Nasu R, Hemmi H, Yoshimura T. Mechanism of eukaryotic serine racemase-catalyzed serine dehydration. Biochim Biophys Acta Proteins Proteom 2020; 1868:140460. [PMID: 32474107 DOI: 10.1016/j.bbapap.2020.140460] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 05/14/2020] [Accepted: 05/26/2020] [Indexed: 12/30/2022]
Abstract
Eukaryotic serine racemase (SR) is a pyridoxal 5'-phosphate enzyme belonging to the Fold-type II group, which catalyzes serine racemization and is responsible for the synthesis of D-Ser, a co-agonist of the N-methyl-d-aspartate receptor. In addition to racemization, SR catalyzes the dehydration of D- and L-Ser to pyruvate and ammonia. The bifuctionality of SR is thought to be important for D-Ser homeostasis. SR catalyzes the racemization of D- and L-Ser with almost the same efficiency. In contrast, the rate of L-Ser dehydration catalyzed by SR is much higher than that of D-Ser dehydration. This has caused the argument that SR does not catalyze the direct D-Ser dehydration and that D-Ser is first converted to L-Ser, then dehydrated. In this study, we investigated the substrate and solvent isotope effect of dehydration of D- and L-Ser catalyzed by SR from Dictyostelium discoideum (DdSR) and demonstrated that the enzyme catalyzes direct D-Ser dehydration. Kinetic studies of dehydration of four Thr isomers catalyzed by D. discoideum and mouse SRs suggest that SR discriminates the substrate configuration at C3 but not at C2. This is probably the reason for the difference in efficiency between L- and D-Ser dehydration catalyzed by SR.
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Affiliation(s)
- Tomokazu Ito
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi 464-8601, Japan
| | - Mai Matsuoka
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi 464-8601, Japan
| | - Masaru Goto
- Department of Biomolecular Science, Faculty of Science, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan.
| | - Soichiro Watanabe
- Department of Biomolecular Science, Faculty of Science, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan
| | - Taichi Mizobuchi
- Department of Biomolecular Science, Faculty of Science, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan
| | - Kazuma Matsushita
- Department of Biomolecular Science, Faculty of Science, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan
| | - Ryoma Nasu
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi 464-8601, Japan
| | - Hisashi Hemmi
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi 464-8601, Japan
| | - Tohru Yoshimura
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi 464-8601, Japan.
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23
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Akiyama T, Toda S, Kimura N, Mogami Y, Hanaoka Y, Tokorodani C, Ito T, Miyahara H, Hyodo Y, Kobayashi K. Vitamin B6 in acute encephalopathy with biphasic seizures and late reduced diffusion. Brain Dev 2020; 42:402-407. [PMID: 32107100 DOI: 10.1016/j.braindev.2020.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/27/2020] [Accepted: 02/12/2020] [Indexed: 11/16/2022]
Abstract
BACKGROUND The initial presentation of acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is indistinguishable from that of complex febrile seizures (FS), which poses a great diagnostic challenge for clinicians. Excitotoxicity is speculated to be the pathogenesis of AESD. Vitamin B6 (VB6) is essential for the biosynthesis of gamma-aminobutyric acid, an inhibitory neurotransmitter. The aim of this study is to investigate our hypothesis that VB6 deficiency in the brain may play a role in AESD. METHODS We obtained cerebrospinal fluid (CSF) samples from pediatric patients with AESD after early seizures and those with FS. We measured pyridoxal 5'-phosphate (PLP) and pyridoxal (PL) concentrations in the CSF samples using high-performance liquid chromatography with fluorescence detection. RESULTS The subjects were 5 patients with AESD and 17 patients with FS. Age did not differ significantly between AESD and FS. In AESD, CSF PLP concentration was marginally lower (p = 0.0999) and the PLP-to-PL ratio was significantly (p = 0.0417) reduced compared to those in FS. CONCLUSIONS Although it is impossible to conclude that low PLP concentration and PLP-to-PL ratio are causative of AESD, this may be a risk factor for developing AESD. When combined with other markers, this finding may be useful in distinguishing AESD from FS upon initial presentation.
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Affiliation(s)
- Tomoyuki Akiyama
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan; Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
| | - Soichiro Toda
- Department of Pediatrics, Kameda Medical Center, Chiba, Japan
| | - Nobusuke Kimura
- Department of Pediatrics, Japanese Red Cross Otsu Hospital, Shiga, Japan
| | - Yukiko Mogami
- Department of Pediatric Neurology, Osaka Women's and Children's Hospital, Osaka, Japan
| | - Yoshiyuki Hanaoka
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan
| | - Chiho Tokorodani
- Department of Pediatrics, Kochi Health Sciences Center, Kochi, Japan
| | - Tomoshiro Ito
- Department of Pediatrics, Sapporo City General Hospital, Hokkaido, Japan
| | - Hiroyuki Miyahara
- Department of Pediatrics, Kurashiki Central Hospital, Okayama, Japan
| | - Yuki Hyodo
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan; Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Katsuhiro Kobayashi
- Department of Child Neurology, Okayama University Hospital, Okayama, Japan; Department of Child Neurology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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24
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Ryan KM, Allers KA, Harkin A, McLoughlin DM. Blood plasma B vitamins in depression and the therapeutic response to electroconvulsive therapy. Brain Behav Immun Health 2020; 4:100063. [PMID: 34589848 PMCID: PMC8474603 DOI: 10.1016/j.bbih.2020.100063] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/22/2020] [Accepted: 03/22/2020] [Indexed: 02/07/2023] Open
Abstract
A growing body of research has indicated a role for B vitamins in depression, with some previous studies suggesting that B vitamin status in patients with depression can impact on antidepressant response. Here we aimed to investigate B vitamin plasma concentrations in medicated patients with depression (n = 94) compared to age- and sex-matched healthy controls (n = 57), and in patients with depression after electroconvulsive therapy (ECT) in a real-world clinical setting. Our results show that nicotinamide (vitamin B3), N1-methylnicotinamide (vitamin B3 metabolite), and pyridoxal 5'-phosphate (PLP; vitamin B6) concentrations were significantly reduced in patients with depression compared to controls. The Cohen's d effect sizes for nicotinamide, N1-methylnicotinamide, and PLP were moderate-large (-0.47, -0.51, and -0.59, respectively), and likely to be of clinical relevance. Functional biomarkers of vitamin B6 status (PAr index, 3-hydroxykynurenine: hydroxyanthranilic acid ratio, 3-hydroxykynurenine: xanthurenic acid ratio, and HKr) were elevated in depressed patients compared to controls, suggestive of reduced vitamin B6 function. Over 30% of the patient cohort were found to have low to deficient PLP concentrations, and exploratory analyses revealed that these patients had higher IL-6 and CRP concentrations compared to patients with PLP levels within the normal range. Treatment with ECT did not alter B vitamin concentrations, and B vitamin concentrations were not associated with depression severity or the therapeutic response to ECT. Overall, reduced plasma PLP, nicotinamide, and N1-methylnicotinamide concentrations could have wide ranging effects on pathways and systems implicated in depression. Further studies are required to understand the reasons why patients with depression present with low plasma B vitamin concentrations.
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Affiliation(s)
- Karen M Ryan
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland.,Department of Psychiatry, Trinity College Dublin, St. Patrick's University Hospital, James Street, Dublin 8, Ireland
| | - Kelly A Allers
- Central Nervous System Disease Research, Boehringer Ingelheim Pharma GmbH + Co. KG, Birkendorferstrabe 65, Biberach a.d. Riss, Germany
| | - Andrew Harkin
- Neuropsychopharmacology Research Group, School of Pharmacy and Pharmaceutical Sciences & Trinity College Institute of Neuroscience, Trinity College, Dublin 2, Ireland
| | - Declan M McLoughlin
- Trinity College Institute of Neuroscience, Trinity College Dublin, Dublin 2, Ireland.,Department of Psychiatry, Trinity College Dublin, St. Patrick's University Hospital, James Street, Dublin 8, Ireland
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25
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Mueser TC, Drago V, Kovalevsky A, Dajnowicz S. Pyridoxal 5'-phosphate dependent reactions: Analyzing the mechanism of aspartate aminotransferase. Methods Enzymol 2020; 634:333-359. [PMID: 32093839 DOI: 10.1016/bs.mie.2020.01.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Enzyme catalysis is the primary activity in energy and information metabolism and enzyme cofactors are key to the catalytic ability of most enzymes. Pyridoxal 5'-phosphate (PLP) cofactor, derived from Vitamin B6, is widely distributed in nature and has significant latitude in catalytic diversity. X-ray crystallography has revealed the structures of diverse PLP dependent enzymes from multiple families. But these structures are incomplete, lacking the positions of protons essential for understanding enzymatic mechanisms. Here, we review the diversity of PLP and discuss the use of neutron crystallography and joint X-ray/neutron refinement of Fold Type I aspartate aminotransferase to visualize the positions of protons in both the internal and external aldimine forms. Strategies used to prepare extremely large crystals required for neutron diffraction and the approach to data refinement including the PLP cofactor are discussed. The observed positions of protons, including one located in a previously unknown low-barrier hydrogen bond, have been used to create more accurate models for computational analysis. The results revealed a new mechanism for the transaminase reaction where hyperconjugation is key to reducing the energy barrier which finally provides a clear explanation of the Dunathan alignment.
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Affiliation(s)
- Timothy C Mueser
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH, United States.
| | - Victoria Drago
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH, United States
| | - Andrey Kovalevsky
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
| | - Steven Dajnowicz
- Department of Chemistry and Biochemistry, University of Toledo, Toledo, OH, United States; Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, TN, United States
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26
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Stojanovski BM, Hunter GA, Na I, Uversky VN, Jiang RHY, Ferreira GC. 5-Aminolevulinate synthase catalysis: The catcher in heme biosynthesis. Mol Genet Metab 2019; 128:178-189. [PMID: 31345668 PMCID: PMC6908770 DOI: 10.1016/j.ymgme.2019.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/27/2019] [Accepted: 06/07/2019] [Indexed: 01/26/2023]
Abstract
5-Aminolevulinate (ALA) synthase (ALAS), a homodimeric pyridoxal-5'-phosphate (PLP)-dependent enzyme, catalyzes the first step of heme biosynthesis in metazoa, fungi and α-proteobacteria. In this review, we focus on the advances made in unraveling the mechanism of the ALAS-catalyzed reaction during the past decade. The interplay between the PLP cofactor and the protein moiety determines and modulates the multi-intermediate reaction cycle of ALAS, which involves the decarboxylative condensation of two substrates, glycine and succinyl-CoA. Substrate binding and catalysis are rapid, and product (ALA) release dominates the overall ALAS kinetic mechanism. Interconversion between a catalytically incompetent, open conformation and a catalytically competent, closed conformation is linked to ALAS catalysis. Reversion to the open conformation, coincident with ALA dissociation, defines the slowest step of the reaction cycle. These findings were further substantiated by introducing seven mutations in the16-amino acid loop that gates the active site, yielding an ALAS variant with a greatly increased rate of catalytic turnover and heightened specificity constants for both substrates. Recently, molecular dynamics (MD) simulation analysis of various dimeric ALAS forms revealed that the seven active site loop mutations caused the proteins to adopt different conformations. In particular, the emergence of a β-strand in the mutated loop, which interacted with two preexisting β-strands to form an anti-parallel three-stranded β-sheet, conferred the murine heptavariant with a more stable open conformation and prompted faster product release than wild-type mALAS2. Moreover, the dynamics of the mALAS2 active site loop anti-correlated with that of the 35 amino acid C-terminal sequence. This led us to propose that this C-terminal extension, which is absent in prokaryotic ALASs, finely tunes mammalian ALAS activity. Based on the above results, we extend our previous proposal to include that discovery of a ligand inducing the mammalian C-terminal extension to fold offers a good prospect for the development of a new drug for X-linked protoporphyria and/or other porphyrias associated with enhanced ALAS activity and/or porphyrin accumulation.
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Affiliation(s)
- Bosko M Stojanovski
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
| | - Gregory A Hunter
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Insung Na
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia
| | - Rays H Y Jiang
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Gloria C Ferreira
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA; Department of Chemistry, College of Arts and Sciences, University of South Florida, Tampa, FL 33612, USA.
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27
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Kwon S, Lee JH, Kim CM, Ha HJ, Lee SH, Lee CS, Jeon JH, So I, Park HH. Structural insights into the enzyme specificity of a novel ω-transaminase from the thermophilic bacterium Sphaerobacter thermophilus. J Struct Biol 2019; 208:107395. [PMID: 31560999 DOI: 10.1016/j.jsb.2019.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 09/22/2019] [Accepted: 09/24/2019] [Indexed: 10/26/2022]
Abstract
Transaminases are pyridoxal 5'-phosphate-dependent enzymes that reversibly catalyze transamination reactions from an amino group donor substrate to an amino group acceptor substrate. ω-Transaminases (ωTAs) utilize compounds with an amino group not at α-carbon position as their amino group donor substrates. Recently, a novel ωTA with broad substrate specificity and high thermostability from the thermophilic bacterium Sphaerobacter thermophilus (St-ωTA) has been reported. Although St-ωTA has been biochemically characterized, little is known about its determinants of substrate specificity. In the present study, we determined the crystal structure of St-ωTA at 1.9 Å resolution to clarify in detail its mechanism of substrate recognition. The structure of St-ωTA revealed that it has a voluminous active site resulting from the unique spatial arrangement of residues comprising its active site. In addition, our molecular docking simulation results suggest that substrate compounds may bind to active site residues via electrostatic interactions or hydrophobic interactions that can be induced by subtle rearrangements of active site residues. On the basis of these structural analyses, we propose a plausible working model of the enzymatic mechanism of St-ωTA. Our results provide profound structural insights into the substrate specificity of St-ωTA and extend the boundaries of knowledge of TAs.
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Affiliation(s)
- Sunghark Kwon
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Jun Hyuck Lee
- Unit of Research for Practical Application, Korea Polar Research Institute, Incheon 21990, Republic of Korea
| | - Chang Min Kim
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Hyun Ji Ha
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Sung Hoon Lee
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea
| | - Chang Sup Lee
- College of Pharmacy and Research Institute of Pharmaceutical Science, Gyeongsang National University, Jinju 52828, Republic of Korea
| | - Ju-Hong Jeon
- Department of Physiology and Biomedical Sciences, Institute of Human-Environment Interface Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Insuk So
- Department of Physiology and Biomedical Sciences, Institute of Human-Environment Interface Biology, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Hyun Ho Park
- College of Pharmacy, Chung-Ang University, Seoul 06974, Republic of Korea.
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28
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Kwon S, Park HH. Structural Consideration of the Working Mechanism of Fold Type I Transaminases From Eubacteria: Overt and Covert Movement. Comput Struct Biotechnol J 2019; 17:1031-1039. [PMID: 31452855 PMCID: PMC6698932 DOI: 10.1016/j.csbj.2019.07.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 07/12/2019] [Accepted: 07/19/2019] [Indexed: 12/18/2022] Open
Abstract
Transaminases (TAs) reversibly catalyze the transfer reaction of an amino group between an amino group donor and an amino group acceptor, using pyridoxal 5′-phosphate (PLP) as a cofactor. TAs are categorized according to the amino group position of the donor substrate and respective TAs recognize their own specific substrates. Over the past decade, a number of TA structures have been determined by X-ray crystallography. On the basis of the structural information, the detailed mechanism of substrate recognition by TAs has also been elucidated. In this review, fold type I TAs are addressed intensively. Comparative studies on structural differences between the apo and holo forms of fold type I TAs have demonstrated that regions containing the active site exhibit structural plasticity in the apo form, facilitating PLP insertion into the active site. In addition, given that TAs recognize two different kinds of substrates, they possess dual substrate specificity. It is known that spatial rearrangements of active site residues occur upon binding of the substrates. Intriguingly, positively charged residues are predominantly distributed at the active site cavity. The electric field generated by such charge distributions may attract negatively charged molecules, such as PLP and amino group acceptors, into the active site. Indeed, TAs show remarkable dynamics in diverse aspects. In this review, we describe the comprehensive working mechanism of fold type I TAs, with a focus on conformational changes.
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Affiliation(s)
| | - Hyun Ho Park
- Corresponding author at: College of Pharmacy, Chung-Ang University, Dongjak-gu, Seoul 06974, Republic of Korea.
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29
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Montioli R, Battini R, Paiardini A, Tolve M, Bertoldi M, Carducci C, Leuzzi V, Borri Voltattorni C. A novel compound heterozygous genotype associated with aromatic amino acid decarboxylase deficiency: Clinical aspects and biochemical studies. Mol Genet Metab 2019; 127:132-137. [PMID: 31104889 DOI: 10.1016/j.ymgme.2019.05.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 05/07/2019] [Accepted: 05/07/2019] [Indexed: 11/25/2022]
Abstract
Aromatic amino acid decarboxylase (AADC) deficiency is a rare autosomal neurometabolic disorder caused by a deficit of AADC, a pyridoxal 5'-phosphate (PLP)-dependent enzyme, which catalyzes the synthesis of dopamine and serotonin. While many studies have highlighted the molecular defects of the homozygous pathogenic variants, so far only a study investigated heterozygous variants at protein level. Here, we report a clinical case of one AADC deficiency compound heterozygous patient bearing the A91V mutation and the novel C410G mutation. To elucidate its enzymatic phenotype, the A91V and C410G homodimers were first expressed in Escherichia coli, purified and characterized. Although both apo variants display an unaltered overall tertiary structure, they show a ̴ 20-fold decreased PLP binding affinity. The C410G mutation only causes a ̴ 4-fold decrease of the catalytic efficiency, while the A91V mutation causes a 1300-fold decrease of the kcat/Km, and changes in the holoAADC consisting in a marked alteration of the tertiary structure and the coenzyme microenvironment. Structural analyses of these mutations are in agreement with these data. Unfortunately, the C410G/A91V heterodimer was constructed, expressed and purified in rather modest amount. Anyway, measurements of decarboxylase activity indicate that its putative kcat value is lower than that predicted by averaging the kcat values of the two parental enzymes. This indicates a negative interallelic complementation between the C410G and A91V monomers. Overall, this study allowed to relate the clinical to the enzymatic phenotype of the patient and to extend knowledge in the clinical and molecular pathogenesis of AADC deficiency.
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Affiliation(s)
- Riccardo Montioli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Roberta Battini
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy; IRCCS Fondazione Stella Maris, Pisa, Italy
| | - Alessandro Paiardini
- Department of Biochemical Sciences "A. Rossi Fanelli", University of Roma "La Sapienza", Roma, Italy
| | - Manuela Tolve
- Department of Experimental Medicine, University of Roma "La Sapienza", Roma, Italy; Clinical Pathology Unit, PoliclinicoUmberto 1, Roma, Italy
| | - Mariarita Bertoldi
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Carla Carducci
- Department of Experimental Medicine, University of Roma "La Sapienza", Roma, Italy
| | - Vincenzo Leuzzi
- Department of Human Neuroscience, University of Roma "La Sapienza", Roma, Italy.
| | - Carla Borri Voltattorni
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
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Kishnani PS, Rockman-Greenberg C, Rauch F, Bhatti MT, Moseley S, Denker AE, Watsky E, Whyte MP. Five-year efficacy and safety of asfotase alfa therapy for adults and adolescents with hypophosphatasia. Bone 2019; 121:149-162. [PMID: 30576866 DOI: 10.1016/j.bone.2018.12.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 12/11/2018] [Accepted: 12/13/2018] [Indexed: 12/12/2022]
Abstract
Hypophosphatasia (HPP) features low tissue-nonspecific alkaline phosphatase (TNSALP) isoenzyme activity resulting in extracellular accumulation of its substrates including pyridoxal 5'-phosphate (PLP), the principal circulating form of vitamin B6, and inorganic pyrophosphate (PPi), a potent inhibitor of mineralization. Asfotase alfa is an enzyme replacement therapy developed to treat HPP. This multinational, randomized, open-label study (NCT01163149; EudraCT 2010-019850-42) evaluated the efficacy and safety of asfotase alfa in adults and adolescents 13-66 years of age with HPP. The study comprised a 6-month primary treatment period and a 4.5-year extension phase. In the primary treatment period, 19 patients were randomized to receive asfotase alfa 0.3 mg/kg/d subcutaneously (SC; n = 7), asfotase alfa 0.5 mg/kg/d SC (n = 6), or no treatment (control; n = 6) for 6 months. In the extension phase, patients received asfotase alfa (0.5 mg/kg/d for 6 mo-1 y, then 1 mg/kg/d 6 d/wk). During the primary treatment period, changes from Baseline to Month 6 in plasma PLP and PPi concentrations (coprimary efficacy measure) were greater in the combined asfotase alfa group compared with the control group, reaching statistical significance for PLP (P = 0.0285) but not for PPi (P = 0.0715). However, for the total cohort, the within subject changes in both PLP and PPi after 6 months and over 5 years of treatment with asfotase alfa were significant (P < 0.05). Secondary efficacy measures included transiliac crest histomorphometry, dual-energy X-ray absorptiometry (DXA), and the 6-Minute Walk Test (6MWT). A significant decrease from Baseline in mineralization lag time was observed in the combined asfotase alfa group at Year 1. There were no significant differences between treated and control patients in DXA mean bone mineral density results at 6 months; Z-scores and T-scores were within the expected range for age at Baseline and remained so over 5 years of treatment. On the 6MWT, median (min, max) distance walked increased from 355 (10, 620; n = 19) meters before treatment to 450 (280, 707; n = 13) meters at 5 years (P < 0.05). Results for the exploratory outcome measures suggested improvements in gross motor function, muscle strength, and patient-reported functional disability over 5 years of treatment. There were no deaths during this study. Asfotase alfa was generally well tolerated; the most common adverse events were mild to moderate injection site reactions. This study suggests that in adults and adolescents with pediatric-onset HPP, treatment with asfotase alfa is associated with normalization of circulating TNSALP substrate levels and improved functional abilities.
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Affiliation(s)
| | - Cheryl Rockman-Greenberg
- The University of Manitoba, Rady Faculty of Health Sciences, Max Rady College of Medicine, Children's Hospital Research Institute of Manitoba, Winnipeg, Manitoba, Canada.
| | - Frank Rauch
- McGill University, Shriners Hospital for Children, Montreal, Quebec, Canada.
| | - M Tariq Bhatti
- Duke Eye Center, Duke University Medical Center, Durham, NC, USA
| | | | | | - Eric Watsky
- Alexion Pharmaceuticals, Inc., Boston, MA, USA.
| | - Michael P Whyte
- Center for Metabolic Bone Disease and Molecular Research, Shriners Hospital for Children, St. Louis, MO, USA; Division of Bone and Mineral Diseases, Department of Internal Medicine, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, MO, USA.
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Zhang J, Weng H, Zhou Z, Du G, Kang Z. Engineering of multiple modular pathways for high-yield production of 5-aminolevulinic acid in Escherichia coli. Bioresour Technol 2019; 274:353-360. [PMID: 30537593 DOI: 10.1016/j.biortech.2018.12.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 11/30/2018] [Accepted: 12/01/2018] [Indexed: 06/09/2023]
Abstract
5-aminolevulinic acid (ALA), an important precursor of tetrapyrroles, has various applications in medicine and agriculture fields. Several methods have been adopted to enhance ALA synthesis in our previous studies. In this study, systematic metabolic engineering strategies were implemented to further improve ALA production in Escherichia coli. Firstly, hemA and hemL with different strength of RBS from the artificially constructed mutation libraries were randomly assembled to balance metabolic flux. Then the expression of ALA dehydratase was rationally regulated by replacing promoter with fliCp to weaken ALA catabolism. Besides, the activity of glutamate-1-semialdehyde aminotransferase was increased through strengthening the native biosynthesis pathway of cofactor pyridoxal 5'-phosphate. Moreover, plasmid stability was improved by 21.4% by deleting recA and endA in the recombinant. Finally, stepwise improvements in ALA production were increased to 5.25 g/L with a pH two-stage strategy in a 3-L fermenter. This study proved the importance of metabolic balance in the pathway.
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Affiliation(s)
- Junli Zhang
- School of Life Sciences, Taishan Medical University, Tai'an 271016, China; The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Huanjiao Weng
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Zhengxiong Zhou
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Guocheng Du
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Zhen Kang
- The Key Laboratory of Industrial Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, China; The Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
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Gamov GA, Zavalishin MN, Sharnin VA. Comment on the frequently used method of the metal complex-DNA binding constant determination from UV-Vis data. Spectrochim Acta A Mol Biomol Spectrosc 2019; 206:160-164. [PMID: 30099313 DOI: 10.1016/j.saa.2018.08.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 08/02/2018] [Accepted: 08/04/2018] [Indexed: 06/08/2023]
Abstract
Present contribution describes the UV-Vis study of the mixture of Cu(II) ions, pyridoxal 5'-phosphate nicotinoyl hydrazone and DNA. Neither free hydrazone nor its copper(II) complex interacts with DNA under the given concentration conditions. The changes in the UV-Vis spectra of the mixture containing metal complex and DNA are caused by partial dissociation of the coordination compound and complexation of the released Cu(II) ions with DNA. This result was obtained by the analysis of a number of the reactions that could occur in the solution of Cu(II) ions, buffer components (namely, Tris), ligand (hydrazone), and DNA.
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Affiliation(s)
- G A Gamov
- Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Sheremetevskii ave. 7, Russia.
| | - M N Zavalishin
- Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Sheremetevskii ave. 7, Russia
| | - V A Sharnin
- Ivanovo State University of Chemistry and Technology, 153000 Ivanovo, Sheremetevskii ave. 7, Russia
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Amornwatcharapong W, Maenpuen S, Chitnumsub P, Leartsakulpanich U, Chaiyen P. Human and Plasmodium serine hydroxymethyltransferases differ in rate-limiting steps and pH-dependent substrate inhibition behavior. Arch Biochem Biophys 2017; 630:91-100. [PMID: 28760597 DOI: 10.1016/j.abb.2017.07.017] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 01/14/2023]
Abstract
Serine hydroxymethyltransferase (SHMT), an essential enzyme for cell growth and development, catalyzes the transfer of -CH2OH from l-serine to tetrahydrofolate (THF) to form glycine and 5,10-methylenetetrahydrofolate (MTHF) which is used for nucleotide synthesis. Insights into the ligand binding and inhibition properties of human cytosolic SHMT (hcSHMT) and Plasmodium SHMT (PvSHMT) are crucial for designing specific drugs against malaria and cancer. The results presented here revealed strong and pH-dependent THF inhibition of hcSHMT. In contrast, in PvSHMT, THF inhibition and the influence of pH were not as pronounced. Ligand binding experiments performed at various pH values indicated that the hcSHMT:Gly complex binds THF more tightly at lower pH conditions, while the binding affinity of the PvSHMT:Gly complex for THF is not pH-dependent. Pre-steady state kinetic (rapid-quench) analysis of hcSHMT showed burst kinetics, indicating that glycine formation occurs fastest in the first turnover relative to the subsequent turnovers i.e. glycine release is the rate-limiting step in the hcSHMT reaction. All data suggest that excess THF likely binds E:Gly binary complex and forms the E:Gly:THF dead-end complex before glycine is released. A unique flap motif found in the structure of hcSHMT may be the key structural feature that imparts these described characteristics of hcSHMT.
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Affiliation(s)
- Watcharee Amornwatcharapong
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Somchart Maenpuen
- Department of Biochemistry, Faculty of Science, Burapha University, Chonburi 20131, Thailand
| | - Penchit Chitnumsub
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani 12120, Thailand
| | - Ubolsree Leartsakulpanich
- National Center for Genetic Engineering and Biotechnology, National Science and Technology Development Agency, Pathumthani 12120, Thailand.
| | - Pimchai Chaiyen
- Department of Biochemistry and Center for Excellence in Protein and Enzyme Technology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand; Department of Biomolecular Science and Engineering, School of Biomolecular Science & Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Rayong 21210, Thailand.
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Abstract
Human ornithine δ-aminotransferase (hOAT) (EC 2.6.1.13) is a mitochondrial pyridoxal 5′-phosphate (PLP)-dependent aminotransferase whose deficit is associated with gyrate atrophy, a rare autosomal recessive disorder causing progressive blindness and chorioretinal degeneration. Here, both the apo- and holo-form of recombinant hOAT were characterized by means of spectroscopic, kinetic, chromatographic and computational techniques. The results indicate that apo and holo-hOAT (a) show a similar tertiary structure, even if apo displays a more pronounced exposure of hydrophobic patches, (b) exhibit a tetrameric structure with a tetramer-dimer equilibrium dissociation constant about fivefold higher for the apoform with respect to the holoform, and (c) have apparent Tm values of 46 and 67 °C, respectively. Moreover, unlike holo-hOAT, apo-hOAT is prone to unfolding and aggregation under physiological conditions. We also identified Arg217 as an important hot-spot at the dimer–dimer interface of hOAT and demonstrated that the artificial dimeric variant R217A exhibits spectroscopic properties, Tm values and catalytic features similar to those of the tetrameric species. This finding indicates that the catalytic unit of hOAT is the dimer. However, under physiological conditions the apo-tetramer is slightly less prone to unfolding and aggregation than the apo-dimer. The possible implications of the data for the intracellular stability and regulation of hOAT are discussed.
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Affiliation(s)
- Riccardo Montioli
- Department of Neuroscience, Biomedicine and Movement Sciences (Section of Biological Chemistry), University of Verona, Strada Le Grazie 8, 37134, Verona, Italy.
| | | | - Carla Borri Voltattorni
- Department of Neuroscience, Biomedicine and Movement Sciences (Section of Biological Chemistry), University of Verona, Strada Le Grazie 8, 37134, Verona, Italy
| | - Barbara Cellini
- Department of Neuroscience, Biomedicine and Movement Sciences (Section of Biological Chemistry), University of Verona, Strada Le Grazie 8, 37134, Verona, Italy
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Xiong Q, Xu Z, Xu L, Yao Z, Li S, Xu H. Efficient Production of γ-GABA Using Recombinant E. coli Expressing Glutamate Decarboxylase (GAD) Derived from Eukaryote Saccharomyces cerevisiae. Appl Biochem Biotechnol 2017; 183:1390-1400. [PMID: 28656550 DOI: 10.1007/s12010-017-2506-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Accepted: 05/04/2017] [Indexed: 11/30/2022]
Abstract
γ-Aminobutyric acid (γ-GABA) is a non-proteinogenic amino acid, which acts as a major regulator in the central nervous system. Glutamate decarboxylase (namely GAD, EC 4.1.1.15) is known to be an ideal enzyme for γ-GABA production using L-glutamic acid as substrate. In this study, we cloned and expressed GAD gene from eukaryote Saccharomyces cerevisiae (ScGAD) in E. coli BL21(DE3). This enzyme was further purified and its optimal reaction temperature and pH were 37 °C and pH 4.2, respectively. The cofactor of ScGAD was verified to be either pyridoxal 5'-phosphate (PLP) or pyridoxal hydrochloride. The optimal concentration of either cofactor was 50 mg/L. The optimal medium for E. coli-ScGAD cultivation and expression were 10 g/L lactose, 5 g/L glycerol, 20 g/L yeast extract, and 10 g/L sodium chloride, resulting in an activity of 55 U/mL medium, three times higher than that of using Luria-Bertani (LB) medium. The maximal concentration of γ-GABA was 245 g/L whereas L-glutamic acid was near completely converted. These findings provided us a good example for bio-production of γ-GABA using recombinant E. coli expressing a GAD enzyme derived from eukaryote.
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Affiliation(s)
- Qiang Xiong
- College of Food Science and Light Industry, Nanjing Tech University, 211816, Nanjing, People's Republic of China.,State Key Laboratory of Materials-Oriented Chemical Engineering, 210009, Nanjing, People's Republic of China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing, People's Republic of China
| | - Zheng Xu
- College of Food Science and Light Industry, Nanjing Tech University, 211816, Nanjing, People's Republic of China.,State Key Laboratory of Materials-Oriented Chemical Engineering, 210009, Nanjing, People's Republic of China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing, People's Republic of China
| | - Lu Xu
- College of Food Science and Light Industry, Nanjing Tech University, 211816, Nanjing, People's Republic of China.,State Key Laboratory of Materials-Oriented Chemical Engineering, 210009, Nanjing, People's Republic of China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing, People's Republic of China
| | - Zhong Yao
- College of Food Science and Light Industry, Nanjing Tech University, 211816, Nanjing, People's Republic of China.,State Key Laboratory of Materials-Oriented Chemical Engineering, 210009, Nanjing, People's Republic of China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing, People's Republic of China
| | - Sha Li
- College of Food Science and Light Industry, Nanjing Tech University, 211816, Nanjing, People's Republic of China.,State Key Laboratory of Materials-Oriented Chemical Engineering, 210009, Nanjing, People's Republic of China.,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing, People's Republic of China
| | - Hong Xu
- College of Food Science and Light Industry, Nanjing Tech University, 211816, Nanjing, People's Republic of China. .,State Key Laboratory of Materials-Oriented Chemical Engineering, 210009, Nanjing, People's Republic of China. .,Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), Nanjing, People's Republic of China.
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Wang Q, He XM, Chen X, Zhu GT, Wang RQ, Feng YQ. Pyridoxal 5'-phosphate mediated preparation of immobilized metal affinity material for highly selective and sensitive enrichment of phosphopeptides. J Chromatogr A 2017; 1499:30-37. [PMID: 28390667 DOI: 10.1016/j.chroma.2017.03.085] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 03/28/2017] [Accepted: 03/31/2017] [Indexed: 01/02/2023]
Abstract
Phosphorylation is a crucial post-translational modification, which plays pivotal roles in various biological processes. Analysis of phosphopeptides by mass spectrometry (MS) is intractable on account of their low stoichiometry and the ion suppression from non-phosphopeptides. Thus, enrichment of phosphopeptides before MS analysis is indispensable. In this work, we employed pyridoxal 5'-phosphate (PLP), as an immobilized metal affinity chromatography (IMAC) ligand for the enrichment of phosphopeptides. PLP was grafted onto several substrates such as silica (SiO2), oxidized carbon nanotube (OCNT) and silica coated magnetic nanoparticles (Fe3O4@SiO2). Then the metal ions Fe3+, Ga3+ and Ti4+ were incorporated for the selective enrichment of phosphopeptides. It is indicated that Fe3O4@SiO2-PLP-Ti4+ has a superior selectivity towards phosphopeptides under as much as 1000-fold interferences of non-phosphopeptides. Further, Fe3O4@SiO2-PLP-Ti4+ exhibited high efficiency in selective enrichments of phosphopeptides from complex biological samples, including human serum and tryptic digested non-fat milk. Finally, Fe3O4@SiO2-PLP-Ti4+ was successfully employed in the sample pretreatment for profiling phosphopeptides in a tryptic digest of rat brain proteins. Our experimental results evidenced a great potential of this new chelator-based material in phosphoproteomics study.
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Affiliation(s)
- Qian Wang
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China
| | - Xiao-Mei He
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China
| | - Xi Chen
- Wuhan Institute of Biotechnology, Wuhan 430072, PR China
| | - Gang-Tian Zhu
- Key Laboratory of Tectonics and Petroleum Resources (Ministry of Education), China University of Geosciences, Wuhan 430075, PR China
| | - Ren-Qi Wang
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China; College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou 730000, PR China
| | - Yu-Qi Feng
- Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072, PR China.
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Bothra S, Upadhyay Y, Kumar R, Sahoo SK. Applications of vitamin B6 cofactor pyridoxal 5'-phosphate and pyridoxal 5'-phosphate crowned gold nanoparticles for optical sensing of metal ions. Spectrochim Acta A Mol Biomol Spectrosc 2017; 174:1-6. [PMID: 27865135 DOI: 10.1016/j.saa.2016.11.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 11/05/2016] [Accepted: 11/12/2016] [Indexed: 06/06/2023]
Abstract
Vitamin B6 cofactor pyridoxal 5'-phosphate (PLP) and PLP crowned gold nanoparticles (PLP-AuNPs) was applied for the optical chemosensing of metal ions in aqueous medium. PLP showed a visually detectable colour change from colourless to yellow and 'turn-off' fluorescence in the presence of Fe3+. The fluorescence intensity of PLP at 433nm was also blue-shifted and enhanced at 395nm upon addition of Al3+. When the PLP was functionalized over AuNPs surface, the wine red colour of PLP-AuNPs was turned to purplish-blue and the SPR band at ~525nm was red-shifted upon addition of Al3+, Cd2+ and Pb2+ due to the complexation-induced aggregation of nanoparticles. The developed sensing systems exhibited good selectivity and specificity for the detected analytes (Fe3+, Al3+, Cd2+ and Pb2+).
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Affiliation(s)
- Shilpa Bothra
- Department of Applied Chemistry, S.V. National Institute of Technology (SVNIT), Surat 395007, India
| | - Yachana Upadhyay
- Department of Applied Chemistry, S.V. National Institute of Technology (SVNIT), Surat 395007, India
| | - Rajender Kumar
- Department of Applied Chemistry, S.V. National Institute of Technology (SVNIT), Surat 395007, India
| | - Suban K Sahoo
- Department of Applied Chemistry, S.V. National Institute of Technology (SVNIT), Surat 395007, India.
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Huang JY, Butler LM, Midttun Ø, Koh WP, Ueland PM, Wang R, Jin A, Gao YT, Yuan JM. Serum B 6 vitamers (pyridoxal 5'-phosphate, pyridoxal, and 4-pyridoxic acid) and pancreatic cancer risk: two nested case-control studies in Asian populations. Cancer Causes Control 2016; 27:1447-1456. [PMID: 27830400 PMCID: PMC5161671 DOI: 10.1007/s10552-016-0822-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 10/21/2016] [Indexed: 02/05/2023]
Abstract
BACKGROUND Vitamin B6 is an important enzymatic cofactor in pathways relevant for the development of pancreatic cancer. In order to evaluate vitamin B6 as a preventive factor for pancreatic cancer, a biomarker approach is needed to overcome the limitations inherent in self-reported dietary information. METHODS To determine whether levels of serum B6 vitamers, including pyridoxal 5'-phosphate (PLP), pyridoxal (PL), 4-pyridoxic acid (PA), and the PA/(PLP + PL) ratio (PAr), were associated with risk of pancreatic cancer, two nested case-control studies of 187 incident pancreatic cancer cases and 258 individually matched controls were conducted within two prospective cohorts of 81,501 participants in Shanghai, China, and Singapore. PLP, PL, and PA were quantified in pre-diagnostic serum samples. Odds ratios and 95% confidence intervals (CIs) were calculated using conditional logistic regression with adjustment for potential confounders. RESULTS The median (5th-95th percentiles) concentrations of serum PLP among control subjects of the Shanghai and Singapore cohorts were 25.7 (10.0-91.7) nmol/L and 58.1 (20.8-563.0) nmol/L, respectively. In pooled analyses, high serum PLP was associated with a reduced risk of pancreatic cancer (P for trend = 0.048); the adjusted odds ratio for the highest category of PLP (>52.4 nmol/L) was 0.46 (95% CI 0.23, 0.92) compared to vitamin B6 deficiency (<20 nmol/L). No associations were found for serum PL, PA, or PAr with pancreatic cancer risk. CONCLUSIONS Higher concentrations of PLP may protect against the development of pancreatic cancer. The protective effect may be more apparent in populations with low concentrations of circulating vitamin B6.
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Affiliation(s)
- Joyce Y Huang
- Division of Cancer Control and Population Science, University of Pittsburgh Cancer Institute, UPMC Cancer Pavilion, 5150 Centre Avenue - Suite 4C, Pittsburgh, PA, 15232, USA
- Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lesley M Butler
- Division of Cancer Control and Population Science, University of Pittsburgh Cancer Institute, UPMC Cancer Pavilion, 5150 Centre Avenue - Suite 4C, Pittsburgh, PA, 15232, USA.
- Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA.
| | | | - Woon-Puay Koh
- Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - Per M Ueland
- Department of Clinical Science, University of Bergen, Bergen, Norway
- Laboratory of Clinical Biochemistry, Haukeland University Hospital, Bergen, Norway
| | - Renwei Wang
- Division of Cancer Control and Population Science, University of Pittsburgh Cancer Institute, UPMC Cancer Pavilion, 5150 Centre Avenue - Suite 4C, Pittsburgh, PA, 15232, USA
| | - Aizhen Jin
- National Registry of Diseases Office, Health Promotion Board, Singapore, Singapore
| | - Yu-Tang Gao
- Shanghai Jiaotong University, Shanghai, China
| | - Jian-Min Yuan
- Division of Cancer Control and Population Science, University of Pittsburgh Cancer Institute, UPMC Cancer Pavilion, 5150 Centre Avenue - Suite 4C, Pittsburgh, PA, 15232, USA
- Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA, USA
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Taylor CE. A novel treatment for "morning sickness": Nausea of pregnancy could be induced by excess sulfite which molybdenum can help alleviate. Med Hypotheses 2016; 95:31-33. [PMID: 27692161 DOI: 10.1016/j.mehy.2016.08.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/13/2016] [Indexed: 12/28/2022]
Abstract
Nausea and vomiting of pregnancy (NVP) remains difficult to treat. Last century, thalidomide was used to alleviate NVP, but it caused teratogenesis by interfering with angiogenesis. The gasotransmitters hydrogen sulfide (H2S) and nitric oxide are mutually dependent on each other for their angiogenesis-related functions. Pregnancy-related requirements for increased endogenous H2S could create a temporary excess of sulfite, an H2S catabolite, which is toxic and can induce nausea. Sulfite oxidase, a molybdenum-containing enzyme, catalyzes oxidation of sulfite to sulfate, which can then be excreted or reused by the body. Supplementation with molybdenum should facilitate enhanced sulfite oxidase activity, thus lowering gestationally-elevated sulfite levels in the gastrointestinal tract and easing NVP.
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Kim MI, Hong M. Crystal structure and catalytic mechanism of pyridoxal kinase from Pseudomonas aeruginosa. Biochem Biophys Res Commun 2016; 478:300-6. [PMID: 27425248 DOI: 10.1016/j.bbrc.2016.07.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 07/02/2016] [Indexed: 11/20/2022]
Abstract
Pyridoxal kinase is a ubiquitous enzyme essential for pyridoxal 5'-phosphate (PLP) homeostasis since PLP is required for the catalytic activity of a variety of PLP-dependent enzymes involved in amino acid, lipid, and sugar metabolism as well as neurotransmitter biosynthesis. Previously, two catalytic mechanisms were proposed with regard to Pdx kinases, in which either the aspartate or the cysteine residue is involved as a catalytic residue. Because the Pdx kinase of Pseudomonas aeruginosa (PaPdxK) contains both residues, the catalytic mechanism of PaPdxK remains elusive. To elucidate the substrate-recognition and catalytic mechanisms of PaPdxK, the crystal structure of PaPdxK was determined at a 2.0 Å resolution. The PaPdxK structure possesses a channel that can accommodate substrates and a metallic cofactor. Our structure-based biochemical and mutational analyses in combination with modeling studies suggest that PaPdxK catalysis is mediated by an acid-base mechanism through the catalytic acid Asp225 and a helical dipole moment.
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Ito T, Yamauchi A, Hemmi H, Yoshimura T. Ophthalmic acid accumulation in an Escherichia coli mutant lacking the conserved pyridoxal 5'-phosphate-binding protein YggS. J Biosci Bioeng 2016; 122:689-693. [PMID: 27426274 DOI: 10.1016/j.jbiosc.2016.06.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 06/04/2016] [Accepted: 06/17/2016] [Indexed: 10/21/2022]
Abstract
Escherichia coli YggS is a highly conserved pyridoxal 5'-phosphate (PLP)-binding protein whose biochemical function is currently unknown. A previous study with a yggS-deficient E. coli strain (ΔyggS) demonstrated that YggS controls l-Ile- and l-Val-metabolism by modulating 2-ketobutyrate (2-KB), l-2-aminobutyrate (l-2-AB), and/or coenzyme A (CoA) availability in a PLP-dependent fashion. In this study, we found that ΔyggS accumulates an unknown metabolite as judged by amino acid analyses. LC/MS and MS/MS analyses of the compound with propyl chloroformate derivatization, and co-chromatography analysis identified this compound as γ-l-glutamyl-l-2-aminobutyryl-glycine (ophthalmic acid), a glutathione (GSH) analogue in which the l-Cys moiety is replaced by l-2-AB. We also determine the metabolic consequence of the yggS mutation. Absence of YggS initially increases l-2-AB availability, and then causes ophthalmic acid accumulation and CoA limitation in the cell. The expression of a γ-glutamylcysteine synthetase and a glutathione synthetase in a ΔyggS background causes high-level accumulation of ophthalmic acid in the cells (∼1.2 nmol/mg cells) in a minimal synthetic medium. This opens the possibility of a first fermentative production of ophthalmic acid.
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Affiliation(s)
- Tomokazu Ito
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi 464-8601, Japan.
| | - Ayako Yamauchi
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi 464-8601, Japan
| | - Hisashi Hemmi
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi 464-8601, Japan
| | - Tohru Yoshimura
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furou-chou, Chikusa, Nagoya, Aichi 464-8601, Japan
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Montioli R, Paiardini A, Kurian MA, Dindo M, Rossignoli G, Heales SJR, Pope S, Voltattorni CB, Bertoldi M. The novel R347g pathogenic mutation of aromatic amino acid decarboxylase provides additional molecular insights into enzyme catalysis and deficiency. Biochim Biophys Acta 2016; 1864:676-682. [PMID: 26994895 DOI: 10.1016/j.bbapap.2016.03.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Revised: 03/15/2016] [Accepted: 03/15/2016] [Indexed: 10/22/2022]
Abstract
We report here a clinical case of a patient with a novel mutation (Arg347→Gly) in the gene encoding aromatic amino acid decarboxylase (AADC) that is associated with AADC deficiency. The variant R347G in the purified recombinant form exhibits, similarly to the pathogenic mutation R347Q previously studied, a 475-fold drop of kcat compared to the wild-type enzyme. In attempting to unravel the reason(s) for this catalytic defect, we have carried out bioinformatics analyses of the crystal structure of AADC-carbidopa complex with the modelled catalytic loop (residues 328-339). Arg347 appears to interact with Phe103, as well as with both Leu333 and Asp345. We have then prepared and characterized the artificial F103L, R347K and D345A mutants. F103L, D345A and R347K exhibit about 13-, 97-, and 345-fold kcat decrease compared to the wild-type AADC, respectively. However, unlike F103L, the R347G, R347K and R347Q mutants as well as the D345A variant appear to be more defective in catalysis than in protein folding. Moreover, the latter mutants, unlike the wild-type protein and the F103L variant, share a peculiar binding mode of dopa methyl ester consisting of formation of a quinonoid intermediate. This finding strongly suggests that their catalytic defects are mainly due to a misplacement of the substrate at the active site. Taken together, our results highlight the importance of the Arg347-Leu333-Asp345 hydrogen-bonds network in the catalysis of AADC and reveal the molecular basis for the pathogenicity of the variants R347. Following the above results, a therapeutic treatment for patients bearing the mutation R347G is proposed.
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Affiliation(s)
- Riccardo Montioli
- Department of Neurosciences, Biomedicine and Movement, University of Verona, Verona, Italy
| | - Alessandro Paiardini
- Department of Biology and Biotechnology "Charles Darwin", La Sapienza University of Roma, Roma, Italy
| | - Manju A Kurian
- Developmental Neurosciences, UCL-Institute of Child Health, London, UK; Department of Neurology, Great Ormond Street Hospital, London, UK
| | - Mirco Dindo
- Department of Neurosciences, Biomedicine and Movement, University of Verona, Verona, Italy
| | - Giada Rossignoli
- Department of Neurosciences, Biomedicine and Movement, University of Verona, Verona, Italy
| | - Simon J R Heales
- Clinical Chemistry, Great Ormond Street Hospital, London, UK; Neurometabolic Unit, National Hospital of Neurology and Neurosurgery, UK
| | - Simon Pope
- Neurometabolic Unit, National Hospital of Neurology and Neurosurgery, UK
| | | | - Mariarita Bertoldi
- Department of Neurosciences, Biomedicine and Movement, University of Verona, Verona, Italy.
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Trippe BS, Barrentine LW, Curole MV, Tipa E. Nutritional management of patients with diabetic peripheral neuropathy with L-methylfolate-methylcobalamin-pyridoxal-5-phosphate: results of a real-world patient experience trial. Curr Med Res Opin 2016; 32:219-27. [PMID: 26439233 DOI: 10.1185/03007995.2015.1103215] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Current therapies for diabetic peripheral neuropathy with pain mask the painful symptoms while the underlying pathology continues to progress. This study assessed changes in symptoms and quality of life in patients taking a novel prescription medical food, L-methylfolate-methylcobalamin-pyridoxal-5-phosphate (LMF-MC-PP, Metanx ), intended to address the underlying metabolic needs of patients with diabetic peripheral neuropathy. RESEARCH DESIGN AND METHODS Between November 2010 and April 2012, patients rated their experiences before and after using LMF-MC-PP through an automated telephone system that included symptomatic items from the Neuropathy Total Symptom Score-6 (NTSS-6) questionnaire and questions related to quality of life and medication satisfaction. RESULTS A total of 544 patients participated in the study. Patients reported a mean reduction of 35% in NTSS-6 scores from after 12 weeks on LMF-MC-PP. Mean (standard deviation) score was reduced by 1.5 (1.8) at 12 weeks from a baseline of 4.3 (1.5) (p < 0.05). Patients achieved significant reductions in self-reported disruptions in work/school activities, social life, and family life, respectively. Overall pain rating decreased by 32% (p < 0.05). Patients previously treated with medications reported a 52% improvement in medication satisfaction (p < 0.05). CONCLUSIONS In a real-world clinical setting, patients with diabetic peripheral neuropathy treated with LMF-MC-PP achieved significant improvements in total symptom score (NTSS-6) and in quality of life and functioning, together with greater medication satisfaction. A limitation of this study was the use of a survey instrument to collect data on patient outcomes.
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Affiliation(s)
- Bruce S Trippe
- a a Endocrinology Associates of Montgomery , Montgomery , AL , USA
| | - Lori W Barrentine
- b b Department of Research and Development , Nestlé Health Science - Pamlab Inc. , Covington , LA , USA
| | - Melanie V Curole
- b b Department of Research and Development , Nestlé Health Science - Pamlab Inc. , Covington , LA , USA
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Whittaker JW. Intracellular trafficking of the pyridoxal cofactor. Implications for health and metabolic disease. Arch Biochem Biophys 2015; 592:20-6. [PMID: 26619753 DOI: 10.1016/j.abb.2015.11.031] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Revised: 11/09/2015] [Accepted: 11/16/2015] [Indexed: 01/01/2023]
Abstract
The importance of the vitamin B6-derived pyridoxal cofactor for human health has been established through more than 70 years of intensive biochemical research, revealing its fundamental roles in metabolism. B6 deficiency, resulting from nutritional limitation or impaired uptake from dietary sources, is associated with epilepsy, neuromuscular disease and neurodegeneration. Hereditary disorders of B6 processing are also known, and genetic defects in pathways involved in transport of B6 into the cell and its transformation to the pyridoxal-5'-phosphate enzyme cofactor can contribute to cardiovascular disease by interfering with homocysteine metabolism and the biosynthesis of vasomodulatory polyamines. Compared to the processes involved in cellular uptake and processing of the B6 vitamers, trafficking of the PLP cofactor across intracellular membranes is very poorly understood, even though the availability of PLP within subcellular compartments (particularly the mitochondrion) may have important health implications. The aim of this review is to concisely summarize the state of current knowledge of intracellular trafficking of PLP and to identify key directions for future research.
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Affiliation(s)
- James W Whittaker
- Institute of Environmental Health, Division of Environmental and Biomolecular Systems, Oregon Health and Science University, Portland, OR 97239-3098, USA.
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Kudou D, Yasuda E, Hirai Y, Tamura T, Inagaki K. Molecular cloning and characterization of l-methionine γ-lyase from Streptomyces avermitilis. J Biosci Bioeng 2015; 120:380-3. [PMID: 25817696 DOI: 10.1016/j.jbiosc.2015.02.019] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2014] [Revised: 02/25/2015] [Accepted: 02/28/2015] [Indexed: 11/27/2022]
Abstract
A pyridoxal 5'-phosphate-dependent methionine γ-lyase (MGL) was cloned from Streptomyces avermitilis catalyzed the degradation of methionine to α-ketobutyrate, methanethiol, and ammonia. The sav7062 gene (1,242 bp) was corresponded to 413 amino acid residues with a molecular mass of 42,994 Da. The deduced amino acid sequence showed a high degree of similarity to those of other MGL enzymes. The sav7062 gene was overexpressed in Escherichia coli. The enzyme was purified to homogeneity and exhibited the MGL catalytic activities. We cloned the enzyme that has the MGL activity in Streptomyces for the first time.
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Affiliation(s)
- Daizou Kudou
- Department of Biofunctional Chemistry, Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama-shi, Okayama 700-8530, Japan.
| | - Eri Yasuda
- Department of Biofunctional Chemistry, Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama-shi, Okayama 700-8530, Japan.
| | - Yoshiyuki Hirai
- Department of Biofunctional Chemistry, Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama-shi, Okayama 700-8530, Japan.
| | - Takashi Tamura
- Department of Biofunctional Chemistry, Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama-shi, Okayama 700-8530, Japan.
| | - Kenji Inagaki
- Department of Biofunctional Chemistry, Graduate School of Environmental and Life Science, Okayama University, Tsushima-naka 1-1-1, Kita-ku, Okayama-shi, Okayama 700-8530, Japan.
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46
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Ota H, Mushiga M, Yoshimura T, Yoshimune K. Enzyme assay for pyridoxal 5'-phosphate by apo-D-amino acid aminotransferase. J Biosci Bioeng 2015; 120:117-9. [PMID: 25622769 DOI: 10.1016/j.jbiosc.2014.12.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 12/03/2014] [Accepted: 12/04/2014] [Indexed: 11/28/2022]
Abstract
D-amino acid aminotransferase (D-AAT) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme. D-AAT from thermophilic Bacillus sp. YM-1 was inactivated by ultraviolet irradiation. The activity was restored by the addition of PLP and showed a linear correlation with respect to PLP concentrations in the range of 10-40 nM.
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Affiliation(s)
- Hiroki Ota
- Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, 1-2-1 Izumichou, Narashino, Chiba 275-8575, Japan
| | - Masuwo Mushiga
- Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, 1-2-1 Izumichou, Narashino, Chiba 275-8575, Japan
| | - Tohru Yoshimura
- Department of Applied Molecular Biosciences, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Kazuaki Yoshimune
- Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, 1-2-1 Izumichou, Narashino, Chiba 275-8575, Japan.
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47
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Whittaker MM, Penmatsa A, Whittaker JW. The Mtm1p carrier and pyridoxal 5'-phosphate cofactor trafficking in yeast mitochondria. Arch Biochem Biophys 2015; 568:64-70. [PMID: 25637770 DOI: 10.1016/j.abb.2015.01.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 01/21/2015] [Accepted: 01/22/2015] [Indexed: 12/23/2022]
Abstract
Biochemical communication between the cytoplasmic and mitochondrial subsystems of the cell depends on solute carriers in the mitochondrial inner membrane that transport metabolites between the two compartments. We have expressed and purified a yeast mitochondrial carrier protein (Mtm1p, YGR257cp), originally identified as a manganese ion carrier, for biochemical characterization aimed at resolving its function. High affinity, stoichiometric pyridoxal 5'-phosphate (PLP) cofactor binding was characterized by fluorescence titration and calorimetry, and the biochemical effects of mtm1 gene deletion on yeast mitochondria were investigated. The PLP status of the mitochondrial proteome (the mitochondrial 'PLP-ome') was probed by immunoblot analysis of mitochondria isolated from wild type (MTM1(+)) and knockout (MTM1(-)) yeast, revealing depletion of mitochondrial PLP in the latter. A direct activity assay of the enzyme catalyzing the first committed step of heme biosynthesis, the PLP-dependent mitochondrial enzyme 5-aminolevulinate synthase, extends these results, providing a specific example of PLP cofactor limitation. Together, these experiments support a role for Mtm1p in mitochondrial PLP trafficking and highlight the link between PLP cofactor transport and iron metabolism, a remarkable illustration of metabolic integration.
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Affiliation(s)
- Mei M Whittaker
- Institute of Environmental Health, Division of Environmental and Biomolecular Systems, Oregon Health and Science University, Portland, OR 97239-3098, USA
| | - Aravind Penmatsa
- Vollum Institute, Oregon Health and Science University, Portland, OR 97239-3098, USA
| | - James W Whittaker
- Institute of Environmental Health, Division of Environmental and Biomolecular Systems, Oregon Health and Science University, Portland, OR 97239-3098, USA.
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48
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Oppici E, Montioli R, Cellini B. Liver peroxisomal alanine:glyoxylate aminotransferase and the effects of mutations associated with Primary Hyperoxaluria Type I: An overview. Biochim Biophys Acta 2015; 1854:1212-9. [PMID: 25620715 DOI: 10.1016/j.bbapap.2014.12.029] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 12/19/2014] [Accepted: 12/20/2014] [Indexed: 11/21/2022]
Abstract
Liver peroxisomal alanine:glyoxylate aminotransferase (AGT) (EC 2.6.1.44) catalyses the conversion of l-alanine and glyoxylate to pyruvate and glycine, a reaction that allows glyoxylate detoxification. Inherited mutations on the AGXT gene encoding AGT lead to Primary Hyperoxaluria Type I (PH1), a rare disorder characterized by the deposition of calcium oxalate crystals primarily in the urinary tract. Here we describe the results obtained on the biochemical features of AGT as well as on the molecular and cellular effects of polymorphic and pathogenic mutations. A complex scenario on the molecular pathogenesis of PH1 emerges in which the co-inheritance of polymorphic changes and the condition of homozygosis or compound heterozygosis are two important factors that determine the enzymatic phenotype of PH1 patients. All the reported data represent relevant steps toward the understanding of genotype/phenotype correlations, the prediction of the response of the patients to the available therapies, and the development of new therapeutic approaches. This article is part of a Special Issue entitled: Cofactor-dependent proteins: evolution, chemical diversity and bio-applications.
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Anufrieva NV, Faleev NG, Morozova EA, Bazhulina NP, Revtovich SV, Timofeev VP, Tkachev YV, Nikulin AD, Demidkina TV. The role of active site tyrosine 58 in Citrobacter freundii methionine γ-lyase. Biochim Biophys Acta 2015; 1854:1220-8. [PMID: 25584856 DOI: 10.1016/j.bbapap.2014.12.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 12/29/2014] [Accepted: 12/30/2014] [Indexed: 10/24/2022]
Abstract
In the spatial structure of methionine γ-lyase (MGL, EC 4.4.1.11) from Citrobacter freundii, Tyr58 is located at H-bonding distance to the oxygen atom of the phosphate "handle" of pyridoxal 5'-phosphate (PLP). It was replaced for phenylalanine by site-directed mutagenesis. The X-ray structure of the mutant enzyme was determined at 1.96Å resolution. Comparison of spatial structures and absorption spectra of wild-type and mutant holoenzymes demonstrated that the replacement did not result in essential changes of the conformation of the active site Tyr58Phe MGL. The Kd value of PLP for Tyr58Phe MGL proved to be comparable to the Kd value for the wild-type enzyme. The replacement led to a decrease of catalytic efficiencies in both γ- and β-elimination reactions of about two orders of magnitude as compared to those for the wild-type enzyme. The rates of exchange of C-α- and C-β- protons of inhibitors in D2O catalyzed by the mutant form are comparable with those for the wild-type enzyme. Spectral data on the complexes of the mutant form with the substrates and inhibitors showed that the replacement led to a change of rate the limiting step of the physiological reaction. The results allowed us to conclude that Tyr58 is involved in an optimal positioning of the active site Lys210 at some stages of γ- and β-elimination reactions. This article is part of a Special Issue entitled: Cofactor-dependent proteins: evolution, chemical diversity and bio-applications.
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Affiliation(s)
- Natalya V Anufrieva
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow 119991, Russia
| | - Nicolai G Faleev
- A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, ul. Vavilova 28, Moscow 117813, Russia
| | - Elena A Morozova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow 119991, Russia
| | - Natalia P Bazhulina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow 119991, Russia
| | - Svetlana V Revtovich
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow 119991, Russia
| | - Vladimir P Timofeev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow 119991, Russia
| | - Yaroslav V Tkachev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow 119991, Russia
| | - Alexei D Nikulin
- Institute of Protein Research, Russian Academy of Sciences, ul. Institutskaya 4, Pushchino, Moscow Region 142290, Russia
| | - Tatyana V Demidkina
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, ul. Vavilova 32, Moscow 119991, Russia.
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50
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Remesh SG, Ghatge MS, Ahmed MH, Musayev FN, Gandhi A, Chowdhury N, di Salvo ML, Kellogg GE, Contestabile R, Schirch V, Safo MK. Molecular basis of E. coli L-threonine aldolase catalytic inactivation at low pH. Biochim Biophys Acta 2015; 1854:278-83. [PMID: 25560296 DOI: 10.1016/j.bbapap.2014.12.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2014] [Revised: 12/20/2014] [Accepted: 12/25/2014] [Indexed: 11/22/2022]
Abstract
L-Threonine aldolases (TAs), a family of enzymes belonging to the fold-type I pyridoxal 5'-phosphate (PLP) dependent enzymes, play a role in catalyzing the reversible cleavage of l-3-hydroxy-α-amino acids to glycine and the corresponding aldehydes. Threonine aldolases have great biotechnological potential for the syntheses of pharmaceutically relevant drug molecules because of their stereospecificity. The pH-dependency of their catalytic activity, affecting reaction intermediates, led us to study the effect of low-pH on Escherichia coli TA (eTA) structure. We report here a low-pH crystal structure of eTA at 2.1 Å resolution, with a non-covalently bound uncleaved l-serine substrate, and a PLP cofactor bound as an internal aldimine. This structure contrasts with other eTA structures obtained at physiological pH that show products or substrates bound as PLP-external aldimines. The non-productive binding at low-pH is due to an unusual substrate serine binding orientation in which the α-amino group and carboxylate group are in the wrong positions (relative to the active site residues) as a result of protonation of the α-amino group of the serine, as well as the active site histidines, His83 and His126. Protonation of these residues prevents the characteristic nucleophilic attack of the α-amino group of substrate serine on C4' of PLP to form the external aldimine. Our study shows that at low pH the change in charge distribution at the active site can result in substrates binding in a non-productive orientation.
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