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Biochemical, Bioinformatic, and Structural Comparisons of Transketolases and Position of Human Transketolase in the Enzyme Evolution. Biochemistry 2024. [PMID: 38767928 DOI: 10.1021/acs.biochem.3c00714] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2024]
Abstract
Transketolases (TKs) are key enzymes of the pentose phosphate pathway, regulating several other critical pathways in cells. Considering their metabolic importance, TKs are expected to be conserved throughout evolution. However, Tittmann et al. (J Biol Chem, 2010, 285(41): 31559-31570) demonstrated that Homo sapiens TK (hsTK) possesses several structural and kinetic differences compared to bacterial TKs. Here, we study 14 TKs from pathogenic bacteria, fungi, and parasites and compare them with hsTK using biochemical, bioinformatic, and structural approaches. For this purpose, six new TK structures are solved by X-ray crystallography, including the TK of Plasmodium falciparum. All of these TKs have the same general fold as bacterial TKs. This comparative study shows that hsTK greatly differs from TKs from pathogens in terms of enzymatic activity, spatial positions of the active site, and monomer-monomer interface residues. An ubiquitous structural pattern is identified in all TKs as a six-residue histidyl crown around the TK cofactor (thiamine pyrophosphate), except for hsTK containing only five residues in the crown. Residue mapping of the monomer-monomer interface and the active site reveals that hsTK contains more unique residues than other TKs. From an evolutionary standpoint, TKs from animals (including H. sapiens) and Schistosoma sp. belong to a distinct structural group from TKs of bacteria, plants, fungi, and parasites, mostly based on a different linker between domains, raising hypotheses regarding evolution and regulation.
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2
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Structural determination and kinetic analysis of the transketolase from Vibrio vulnificus reveal unexpected cooperative behavior. Protein Sci 2024; 33:e4884. [PMID: 38145310 PMCID: PMC10868444 DOI: 10.1002/pro.4884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 12/07/2023] [Accepted: 12/20/2023] [Indexed: 12/26/2023]
Abstract
Vibrio vulnificus (vv) is a multidrug-resistant human bacterial pathogen whose prevalence is expected to increase over the years. Transketolases (TK), transferases catalyzing two reactions of the nonoxidative branch of the pentose-phosphate pathway and therefore linked to several crucial metabolic pathways, are potential targets for new drugs against this pathogen. Here, the vvTK is crystallized and its structure is solved at 2.1 Å. A crown of 6 histidyl residues is observed in the active site and expected to participate in the thiamine pyrophosphate (cofactor) activation. Docking of fructose-6-phosphate and ferricyanide used in the activity assay, suggests that both substrates can bind vvTK simultaneously. This is confirmed by steady-state kinetics showing a sequential mechanism, on the contrary to the natural transferase reaction which follows a substituted mechanism. Inhibition by the I38-49 inhibitor (2-(4-ethoxyphenyl)-1-(pyrimidin-2-yl)-1H-pyrrolo[2,3-b]pyridine) reveals for the first time a cooperative behavior of a TK and docking experiments suggest a previously undescribed binding site at the interface between the pyrophosphate and pyridinium domains.
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3
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Synthesis of Deoxyketoses from Aliphatic alpha‐Ketoacids and Aldoses Catalysed by Thermostable Transketolase Variants from Geobacillus stearothermophilus. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202201190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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4
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Cleavage of Aliphatic α-Hydroxy Ketones by Evolved Transketolase from Geobacillus stearothermophilus. ACS Catal 2022. [DOI: 10.1021/acscatal.1c05140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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5
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High-Throughput Solid-Phase Assay for Substrate Profiling and Directed Evolution of Transketolase. Chembiochem 2021; 22:2814-2820. [PMID: 34289225 DOI: 10.1002/cbic.202100356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Indexed: 11/10/2022]
Abstract
Thiamine diphosphate-dependent enzymes, and specifically transketolases, form one of the most important families of biocatalytic tools for enantioselective carbon-carbon bond formation yielding various hydroxyketones of biological interest. To enable substrate profiling of transketolases for acceptance of different donors and acceptors, a simple, direct colorimetric assay based on pH reaction variation was developed to establish a high-throughput solid-phase assay. This assay reduces the screening effort in the directed evolution of transketolases, as only active variants are selected for further analysis. Transketolase activity is detected as bicarbonate anions released from the α-ketoacid donor substrate, which causes the pH to rise. A pH indicator, bromothymol blue, which changes color from yellow to blue in alkaline conditions, was used to directly detect, with the naked eye, clones expressing active transketolase variants, obviating enzyme extraction.
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6
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Biocatalysed synthesis of chiral amines: continuous colorimetric assays for mining amine-transaminases. Catal Sci Technol 2021. [DOI: 10.1039/d0cy02070b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Versatile and sensitive continuous colorimetric assays were developed for the high throughput screening of a large collection of amine-TAs from biodiversity, and allowed the discovery of a set of diverse biocatalysts with high synthetic potential.
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8
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d-Serine as a Key Building Block: Enzymatic Process Development and Smart Applications within the Cascade Enzymatic Concept. Org Process Res Dev 2020. [DOI: 10.1021/acs.oprd.0c00024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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Convergent
in situ
Generation of Both Transketolase Substrates
via
Transaminase and Aldolase Reactions for Sequential One‐Pot, Three‐Step Cascade Synthesis of Ketoses. ChemCatChem 2019. [DOI: 10.1002/cctc.201901756] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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10
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Evolved Thermostable Transketolase for Stereoselective Two-Carbon Elongation of Non-Phosphorylated Aldoses to Naturally Rare Ketoses. ACS Catal 2019. [DOI: 10.1021/acscatal.9b01339] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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11
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One‐Pot Cascade Synthesis of (3 S)‐Hydroxyketones Catalyzed by Transketolase viaHydroxypyruvate Generated in Situfrom d‐Serine by d‐Amino Acid Oxidase. Adv Synth Catal 2019. [DOI: 10.1002/adsc.201900109] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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12
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Enantioselective Synthesis ofd- andl-α-Amino Acids by Enzymatic Transamination Using Glutamine as Smart Amine Donor. Adv Synth Catal 2018. [DOI: 10.1002/adsc.201801278] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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13
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Abstract
Transketolases (TKs) are ubiquitous thiamine pyrophosphate (TPP)-dependent enzymes of the nonoxidative branch of the pentose phosphate pathway. They are considered as interesting therapeutic targets in numerous diseases and infections (e.g., cancer, tuberculosis, malaria), for which it is important to find specific and efficient inhibitors. Current TK assays require important amounts of enzyme, are time-consuming, and are not specific. Here, we report a new high throughput electrochemical assay based on the oxidative trapping of the TK-TPP intermediate. After electrode characterization, the enzyme loading, electrochemical protocol, and substrate concentration were optimized. Finally, 96 electrochemical assays could be performed in parallel in only 7 min, which allows a rapid screening of TK inhibitors. Then, 1360 molecules of an in-house chemical library were screened and one early lead compound was identified to inhibit TK from E. coli with an IC50 of 63 μM and an inhibition constant ( KI) of 3.4 μM. The electrochemical assay was also used to propose an inhibition mechanism.
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14
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Stereoselective synthesis of γ-hydroxy-α-amino acids through aldolase-transaminase recycling cascades. Chem Commun (Camb) 2018; 53:5465-5468. [PMID: 28466909 DOI: 10.1039/c7cc00742f] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Efficient bi-enzymatic cascades combining aldolases and α-transaminases were designed for the synthesis of γ-hydroxy-α-amino acids. These recycling cascades provide high stereoselectivity, atom economy, and an equilibrium shift of the transamination. l-syn or anti-4-hydroxyglutamic acid and d-anti-4,5-dihydroxynorvaline were thus prepared in 83-95% yield in one step from simple substrates.
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15
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Inside Back Cover: Second-Generation Engineering of a Thermostable Transketolase (TK Gst
) for Aliphatic Aldehyde Acceptors with Either Improved or Reversed Stereoselectivity (ChemBioChem 5/2017). Chembiochem 2017. [DOI: 10.1002/cbic.201700044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Second-Generation Engineering of a Thermostable Transketolase (TKGst) for Aliphatic Aldehyde Acceptors with Either Improved or Reversed Stereoselectivity. Chembiochem 2017; 18:455-459. [DOI: 10.1002/cbic.201600609] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Indexed: 11/07/2022]
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17
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Thiamine biosensor based on oxidative trapping of enzyme-substrate intermediate. Biosens Bioelectron 2017; 87:850-857. [DOI: 10.1016/j.bios.2016.09.049] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 09/09/2016] [Accepted: 09/13/2016] [Indexed: 12/28/2022]
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18
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High-Throughput Electrochemical Screening Assay for Free and Immobilized Oxidases: Electrochemiluminescence and Intermittent Pulse Amperometry. ChemElectroChem 2016. [DOI: 10.1002/celc.201600647] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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19
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Droplet millifluidics for kinetic study of transketolase. BIOMICROFLUIDICS 2016; 10:064103. [PMID: 27917251 PMCID: PMC5106428 DOI: 10.1063/1.4966619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Accepted: 10/18/2016] [Indexed: 06/06/2023]
Abstract
We present a continuous-flow reactor at the millifluidic scale coupled with an online, non-intrusive spectroscopic monitoring method for determining the kinetic parameters of an enzyme, transketolase (TK) used in biocatalysis for the synthesis of polyols by carboligation. The millifluidic system used is based on droplet flow, a well-established method for kinetic chemical data acquisition. The TK assay is based on the direct quantitative measurement of bicarbonate ions released during the transketolase-catalysed reaction in the presence of hydroxypyruvic acid as the donor, thanks to an irreversible reaction: bicarbonate ions react with phosphoenolpyruvate (PEP) in the presence of PEP carboxylase as the first auxiliary enzyme. The oxaloacetate formed is reduced to malate by NADH in the reaction catalysed by malate dehydrogenase as the second auxiliary enzyme. The extent of oxidation of NADH was measured by spectrophotometry at 340 nm. This system gives a direct, quantitative, generic method to evaluate the TK activity versus different substrates. We demonstrate the accuracy of this strategy to determine the enzymatic kinetic parameters and to study the substrate specificity of a thermostable TK from thermophilic microorganism Geobacillus stearothermophilus, offering promising prospects in biocatalysis. Millifluidic systems are useful in this regard as they can be used to rapidly evaluate the TK activity towards various substrates, and also different sets of conditions, identifying the optimal operating environment while minimizing resource consumption and ensuring high control over the operating conditions.
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20
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Chiral Polyol Synthesis Catalyzed by a Thermostable Transketolase Immobilized on Layered Double Hydroxides in Ionic liquids. ChemCatChem 2015. [DOI: 10.1002/cctc.201500524] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Engineering a Thermostable Transketolase for Unnatural Conversion of (2S
)-Hydroxyaldehydes. Adv Synth Catal 2015. [DOI: 10.1002/adsc.201500207] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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22
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23
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24
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Abstract
Directed evolution of a thermostable transketolase yields catalysts with significant improvement in activity, enantioselectivity and substrate scope.
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25
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Profiling substrate specificity of two series of phenethylamine analogs at monoamine oxidase A and B. Org Biomol Chem 2014; 12:8689-95. [DOI: 10.1039/c4ob01377h] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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26
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Optimized immobilization of transketolase from E. coli in MgAl-layered double hydroxides. Colloids Surf B Biointerfaces 2013; 112:452-9. [DOI: 10.1016/j.colsurfb.2013.07.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2013] [Accepted: 07/08/2013] [Indexed: 10/26/2022]
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27
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28
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Thermostable Transketolase fromGeobacillus stearothermophilus:Characterization and Catalytic Properties. Adv Synth Catal 2012. [DOI: 10.1002/adsc.201200590] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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29
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30
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A pH-Based High-Throughput Assay for Transketolase: Fingerprinting of Substrate Tolerance and Quantitative Kinetics. Chembiochem 2012; 13:2290-300. [DOI: 10.1002/cbic.201200364] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Indexed: 11/05/2022]
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31
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One-Pot Cascade Reactions using Fructose-6-phosphate Aldolase: Efficient Synthesis of D-Arabinose 5-Phosphate, D-Fructose 6-Phosphate and Analogues. Adv Synth Catal 2012. [DOI: 10.1002/adsc.201200150] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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32
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Enzymatic and Organocatalyzed Asymmetric Aldolization Reactions for the Synthesis of Thiosugar Scaffolds. European J Org Chem 2011. [DOI: 10.1002/ejoc.201101137] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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33
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Electrochemical detection of transketolase activity using a tyrosinase biosensor. Biosens Bioelectron 2010; 26:139-43. [DOI: 10.1016/j.bios.2010.05.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2010] [Revised: 05/03/2010] [Accepted: 05/17/2010] [Indexed: 11/29/2022]
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34
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A Mutant D-Fructose-6-Phosphate Aldolase (Ala129Ser) with Improved Affinity towards Dihydroxyacetone for the Synthesis of Polyhydroxylated Compounds. Adv Synth Catal 2010. [DOI: 10.1002/adsc.200900772] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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35
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Fluorogenic substrates for the screening assay of transketolase through beta-elimination of umbelliferone—Development, scope and limitations. J Biotechnol 2010; 145:359-66. [DOI: 10.1016/j.jbiotec.2009.12.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 11/23/2009] [Accepted: 12/31/2009] [Indexed: 10/20/2022]
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36
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Amino acid precursors for the detection of transketolase activity in Escherichia coli auxotrophs. Bioorg Med Chem Lett 2009; 19:3767-70. [DOI: 10.1016/j.bmcl.2009.04.111] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 04/21/2009] [Accepted: 04/22/2009] [Indexed: 10/20/2022]
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37
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2-Aminobenzothiazole degradation by free and Ca-alginate immobilized cells of Rhodococcus rhodochrous. CHEMOSPHERE 2009; 75:121-128. [PMID: 19103458 DOI: 10.1016/j.chemosphere.2008.11.021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Revised: 11/07/2008] [Accepted: 11/11/2008] [Indexed: 05/27/2023]
Abstract
2-Aminobenzothiazole (ABT) degradation was investigated using free and immobilized systems during photodegradation under solar light in the presence of Fe(III)-nitrilotriacetic acid (FeNTA), biodegradation by Rhodococcus rhodochrous, and during combined conditions. Ca-alginate hydrogel was chosen as a model matrix and some complementary studies were required to characterize this new system. R. rhodochrous metabolism in this type of environment was monitored by NMR spectroscopy. Neither change in intracellular pH values nor in ATP concentrations was observed by in vivo(31)P NMR, showing that no metabolic modification occurred between free and immobilized cells. (1)H NMR demonstrated that alginate was not used as carbon source by R. rhodochrous. After establishing the pre-treatment protocol by SPE to eliminate solubilised alginate, ABT adsorption on beads and degradation were studied. The same pathways of transformation were observed in suspended and immobilized cell systems. Considering the ABT adsorption phenomenon on alginate beads (8%), the efficiency of the two systems was found to be comparable although the degradation rate was slightly lower with immobilized cells. The most important result was the finding that the positive effect of FeNTA on ABT degradation with immobilized cells was similar to that observed previously with free cells. All these results show that mechanisms observed with free cells can be extrapolated to entrapped cells, i.e. under conditions much closer to those usually encountered in the environment.
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38
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39
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40
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N-METHYL-3,4-DIHYDRO-[3,1]OXAZINOACRIDINE, A USEFUL INTERMEDIATE IN THE SYNTHESIS OF POLYSUBSTITUTED ACRIDINES. SYNTHETIC COMMUN 2006. [DOI: 10.1081/scc-100104417] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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41
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An efficient chemoenzymatic route to dihydroxyacetone phosphate from glycidol for the in situ aldolase-mediated synthesis of monosaccharides. Tetrahedron Lett 2006. [DOI: 10.1016/j.tetlet.2006.03.036] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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42
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Synthesis of stereochemical probes for new fluorogenic assays for yeast transketolase variants. Tetrahedron 2006. [DOI: 10.1016/j.tet.2006.02.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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43
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Improved Straightforward Chemical Synthesis of Dihydroxyacetone Phosphate through Enzymatic Desymmetrization of 2,2-Dimethoxypropane-1,3-diol. J Org Chem 2004; 69:9310-2. [PMID: 15609974 DOI: 10.1021/jo048697k] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dihydroxyacetone phosphate (DHAP) was synthesized in high purity and yield in four steps starting from dihydroxyacetone dimer (DHA) (47% overall yield). DHA was converted into 2,2-dimethoxypropane-1,3-diol, which was desymmetrized by acetylation with lipase AK. The alcohol function was phosphorylated to give dibenzyl phosphate ester 4. From 4, two routes were investigated for large-scale synthesis of DHAP. First, acetate hydrolysis was performed prior to hydrogenolysis of the phosphate protective groups. The acetal hydrolysis was finally catalyzed by the phosphate group itself. Second, acetate and acetal hydrolysis were performed in one single step after hydrogenolysis.
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44
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Abstract
3-Amino- and 3-alkylamino-4-hydroxymethylacridines bearing various substituents on the C ring have been prepared by regioselective electrophilic aromatic substitution of the corresponding 3-aminoacridines and ring opening of the dihydrooxazinoacridine key intermediates. Most of the new compounds show potent cytotoxic activities against murine L1210 (leukemia), human A549 (lung), and HT29 (colon) cancer cell lines. The most cytotoxic molecules, 1 and 13, are active at nanomolar concentrations. As predicted for acridine derivatives, the new compounds intercalate in DNA, but interestingly they do not interfere with topoisomerase I and II activities. The mode of action remains uncertain because intracellular distribution indicated very different behaviors for 1 and 13. Compound 13 is uniformly distributed in the cell both in the cytoplasm and in the nucleus, whereas compound 1 is essentially localized in cytoplasmic granules.
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45
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Regioselective synthesis of angular nitrogen polyheterocycles: dipyrido[3,2-a:2′,3′-c]quinolino[2,3-h]phenazines. Tetrahedron Lett 2002. [DOI: 10.1016/s0040-4039(02)01900-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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46
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Abstract
We report the synthesis of an asymmetric Tröger base containing the two well characterised DNA binding chromophores, proflavine and phenanthroline. The mode of interaction of the hybrid molecule was investigated by circular and linear dichroism experiments and a biochemical assay using DNA topoisomerase I. The data are compatible with a model in which the proflavine moiety intercalates between DNA base pairs and the phenanthroline ring occupies the DNA groove. DNase I cleavage experiments were carried out to investigate the sequence preference of the hybrid ligand and a well resolved footprint was detected at a site encompassing two adjacent 5'-GTC.5-GAC triplets. The sequence preference of the asymmetric molecule is compared to that of the symmetric analogues.
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47
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48
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Synthesis and study of 4-hydroxymethyl-3-(alkylamino)acridines as models of a new class of DNA-intercalating–alkylating agents. ACTA ACUST UNITED AC 2001. [DOI: 10.1039/b107055j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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49
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Abstract
DNA is considered as one of the main targets for anticancer drug design. The planar structure of acridines confers to the molecules the ability to bind DNA by intercalation and therefore to interfere with metabolic processes. A large number of natural alkaloids and synthetic acridine derivatives have been tested as anticancer agents. So far, a few molecules have entered clinical trials and have been approved for chemotherapy. The mechanisms of action are not fully understood. Cytotoxicity may be related to potent enzyme inhibition. Topoisomerase and telomerase activities may be strongly affected by acridines. The affinity of acridines for DNA has also been used to design new active compounds in which a DNA modifying group is tethered to the acridine nucleus. Acridine derivatives display other pharmacological properties such as antibacterial and antimalarial activities. They are also tested for Alzheimer's disease.
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