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The FEBS Journal Mar 2013Thermostable nucleoside phosphorylases are attractive biocatalysts for the synthesis of modified nucleosides. Hence we report on the recombinant expression of three...
Thermostable nucleoside phosphorylases are attractive biocatalysts for the synthesis of modified nucleosides. Hence we report on the recombinant expression of three 'high molecular mass' purine nucleoside phosphorylases (PNPs) derived from the thermophilic bacteria Deinococcus geothermalis, Geobacillus thermoglucosidasius and from the hyperthermophilic archaeon Aeropyrum pernix (5'-methythioadenosine phosphorylase; ApMTAP). Thermostability studies, kinetic analysis and substrate specificities are reported. The PNPs were stable at their optimal temperatures (DgPNP, 55 °C; GtPNP, 70 °C; ApMTAP, activity rising to 99 °C). Substrate properties were investigated for natural purine nucleosides [adenosine, inosine and their C2'-deoxy counterparts (activity within 50-500 U·mg(-1))], analogues with 2'-amino modified 2'-deoxy-adenosine and -inosine (within 0.1-3 U·mg(-1)) as well as 2'-deoxy-2'-fluoroadenosine (9) and its C2'-arabino diastereomer (10, within 0.01-0.03 U·mg(-1)). Our results reveal that the structure of the heterocyclic base (e.g. adenine or hypoxanthine) can play a critical role in the phosphorolysis reaction. The implications of this finding may be helpful for reaction mechanism studies or optimization of reaction conditions. Unexpectedly, the diastereomeric 2'-deoxyfluoro adenine ribo- and arabino-nucleosides displayed similar substrate properties. Moreover, cytidine and 2'-deoxycytidine were found to be moderate substrates of the prepared PNPs, with substrate activities in a range similar to those determined for 2'-deoxyfluoro adenine nucleosides 9 and 10. C2'-modified nucleosides are accepted as substrates by all recombinant enzymes studied, making these enzymes promising biocatalysts for the synthesis of modified nucleosides. Indeed, the prepared PNPs performed well in preliminary transglycosylation reactions resulting in the synthesis of 2'-deoxyfluoro adenine ribo- and arabino- nucleosides in moderate yield (24%).
Topics: Aeropyrum; Amino Acid Sequence; Cloning, Molecular; DNA, Bacterial; Deinococcus; Deoxyadenosines; Enzyme Activation; Enzyme Assays; Enzyme Stability; Escherichia coli; Geobacillus; Glycosylation; Kinetics; Molecular Sequence Data; Phosphorylation; Purine Nucleosides; Purine-Nucleoside Phosphorylase; Pyrimidine Nucleosides; Recombinant Proteins; Sequence Alignment; Solubility; Substrate Specificity; Temperature
PubMed: 23332162
DOI: 10.1111/febs.12143 -
The Journal of Organic Chemistry Mar 2019The Cu(I)- or Ag(I)-catalyzed cycloaddition between 8-ethynyladenine or guanine nucleosides and TMSN gave 8-(1- H-1,2,3-triazol-4-yl) nucleosides in good yields. On the...
The Cu(I)- or Ag(I)-catalyzed cycloaddition between 8-ethynyladenine or guanine nucleosides and TMSN gave 8-(1- H-1,2,3-triazol-4-yl) nucleosides in good yields. On the other hand, reactions of 5-ethynyluracil or cytosine nucleosides with TMSN led to the chemoselective formation of triazoles via Cu(I)-catalyzed cycloaddition or vinyl azides via Ag(I)-catalyzed hydroazidation. These nucleosides with a minimalistic triazolyl modification showed excellent fluorescent properties with 8-(1- H-1,2,3-triazol-4-yl)-2'-deoxyadenosine (8-TrzdA), exhibiting a quantum yield of 44%. The 8-TrzdA 5'-triphosphate was incorporated into duplex DNA containing a one-nucleotide gap by DNA polymerase β.
Topics: Catalysis; Copper; Fluorescence; Molecular Structure; Purine Nucleosides; Pyrimidine Nucleosides; Silver; Triazoles
PubMed: 30806513
DOI: 10.1021/acs.joc.8b03135 -
Nucleosides, Nucleotides & Nucleic Acids 20235'- labeled RNA oligos are important probes to investigate the mechanism of 2'--transphosphorylation reactions. Here we describe a general and efficient synthetic...
5'- labeled RNA oligos are important probes to investigate the mechanism of 2'--transphosphorylation reactions. Here we describe a general and efficient synthetic approach to the phosphoramidite derivatives of 5'- labeled nucleosides starting from the corresponding commercially available 5'--DMT protected nucleosides. Using this method, we prepared 5'--guanosine phosphoramidite in 8 steps (13.2% overall yield), 5'-adenosine phosphoramidite in 9 steps (10.1% overall yield) and 5'--2'-deoxyguanosine phosphoramidite in 6 steps (12.8% overall yield). These 5'- labeled phosphoramidites can be incorporated into RNA oligos by solid phase synthesis for determination of heavy atom isotope effects in RNA 2'--transphosphorylation reactions.
Topics: Purine Nucleosides; Nucleosides; RNA; Organophosphorus Compounds
PubMed: 37233721
DOI: 10.1080/15257770.2023.2218421 -
Journal of Bacteriology May 1982Whole cells and isolated membranes of the marine bacterium MB22 converted nucleotides present in the external medium rapidly into nucleosides and then into bases....
Whole cells and isolated membranes of the marine bacterium MB22 converted nucleotides present in the external medium rapidly into nucleosides and then into bases. Nucleosides and purine bases formed were taken up by distinct transport systems. We found a high-affinity common transport system for adenine, guanine, and hypoxanthine, with a Km of 40 nM. This system was inhibited noncompetitively by purine nucleosides. In addition, two transport systems for nucleosides were present: one for guanosine with a Km of 0.8 microM and another one for inosine and adenosine with a Km of 1.4 microM. The nucleoside transport systems exhibited both mixed and noncompetitive inhibition by different nucleosides other than those translocated; purine and pyrimidine bases had no effect. The transport of nucleosides and purine bases was inhibited by dinitrophenol or azide, thus suggesting that transport is energy dependent. Inside the cell all of the substrates were converted mainly into guanosine, xanthine, and uric acid, but also anabolic products, such as nucleotides and nucleic acids, could be found.
Topics: Adenine; Bacteria; Biological Transport, Active; Cell Membrane; Guanine; Hypoxanthines; Kinetics; Purine Nucleosides; Purine Nucleotides; Purines; Seawater; Water Microbiology
PubMed: 7068527
DOI: 10.1128/jb.150.2.471-482.1982 -
Biopolymers Jan 2021The notion of using synthetic heterocycles instead of the native bases to interface with DNA and RNA has been explored for nearly 60 years. Unnatural bases compatible... (Review)
Review
The notion of using synthetic heterocycles instead of the native bases to interface with DNA and RNA has been explored for nearly 60 years. Unnatural bases compatible with the DNA/RNA coding interface have the potential to expand the genetic code and co-opt the machinery of biology to access new macromolecular function; accordingly, this body of research is core to synthetic biology. While much of the literature on artificial bases focuses on code expansion, there is a significant and growing effort on docking synthetic heterocycles to noncoding nucleic acid interfaces; this approach seeks to illuminate major processes of nucleic acids, including regulation of transcription, translation, transport, and transcript lifetimes. These major avenues of research at the coding and noncoding interfaces have in common fundamental principles in molecular recognition. Herein, we provide an overview of foundational literature in biophysics of base recognition and unnatural bases in coding to provide context for the developing area of targeting noncoding nucleic acid interfaces with synthetic bases, with a focus on systems developed through iterative design and biophysical study.
Topics: Base Pairing; DNA; Hydrogen Bonding; Purine Nucleosides; Pyrimidine Nucleosides; RNA; Synthetic Biology
PubMed: 32969496
DOI: 10.1002/bip.23399 -
Oncology (Williston Park, N.Y.) Jun 2000Pentostatin (Nipent) has demonstrated significant activity as a single agent in patients with low-grade B- and T-cell lymphomas, but thus far, clinical experience with... (Review)
Review
Pentostatin (Nipent) has demonstrated significant activity as a single agent in patients with low-grade B- and T-cell lymphomas, but thus far, clinical experience with combinations of pentostatin and other agents is limited. A study of alternating administration of pentostatin and high-dose interferon-alfa-2a (Roferon A) in cutaneous T-cell lymphoma patients has been undertaken and has demonstrated a 41% response rate, with tolerable toxicity. Studies combining pentostatin with alkylating agents, including chlorambucil (Leukeran) and cyclophosphamide (Cytoxan, Neosar) in patients with chronic lymphocytic leukemia (CLL) have reported significant immunosuppression and have required dose modifications of one or both agents. Recently, a clinical trial was initiated to evaluate the combination of pentostatin and cordycepin, a novel purine analog, in patients with terminal deoxynucleotidyl transferase-positive acute lymphocytic leukemia, based on in vitro data demonstrating the significant synergy of this combination.
Topics: Adult; Aged; Antibiotics, Antineoplastic; Antineoplastic Agents; Antineoplastic Agents, Alkylating; Antineoplastic Combined Chemotherapy Protocols; Clinical Trials as Topic; Deoxyadenosines; Disease-Free Survival; Dose-Response Relationship, Drug; Female; Humans; Interferons; Lymphoma, B-Cell; Lymphoma, T-Cell; Male; Middle Aged; Pentostatin; Purine Nucleosides; Treatment Outcome; Vidarabine
PubMed: 10887642
DOI: No ID Found -
Journal of the American Chemical Society Oct 2022A new approach for synthesizing polycyclic heterofused 7-deazapurine heterocycles and the corresponding nucleosides was developed based on C-H functionalization of...
A new approach for synthesizing polycyclic heterofused 7-deazapurine heterocycles and the corresponding nucleosides was developed based on C-H functionalization of diverse (hetero)aromatics with dibenzothiophene--oxide followed by the Negishi cross-cooupling with bis(4,6-dichloropyrimidin-5-yl)zinc. This cross-coupling afforded a series of (het)aryl-pyrimidines that were converted to fused deazapurine heterocycles through azidation and thermal cyclization. The fused heterocycles were glycosylated to the corresponding 2'-deoxy- and ribonucleosides, and a series of derivatives were prepared by nucleophilic substitutions at position 4. Four series of new polycyclic thieno-fused 7-deazapurine nucleosides were synthesized using this strategy. Most of the deoxyribonucleosides showed good cytotoxic activity, especially for the CCRF-CEM cell line. Phenyl- and thienyl-substituted thieno-fused 7-deazapurine nucleosides were fluorescent, and the former one was converted to 2'-deoxyribonucleoside triphosphate for enzymatic synthesis of labeled oligonucleotides.
Topics: Nucleosides; Cell Line, Tumor; Ribonucleosides; Pyrimidines; Oxides; Zinc; Oligonucleotides; Deoxyribonucleosides; Purine Nucleosides
PubMed: 36245092
DOI: 10.1021/jacs.2c07517 -
Antimicrobial Agents and Chemotherapy Aug 1973Of 142 purines, purine nucleosides, and analogues tested for inhibition of growth of Escherichia coli B Hill, 45 were active. Of these, 27 were evaluated for inhibition...
Of 142 purines, purine nucleosides, and analogues tested for inhibition of growth of Escherichia coli B Hill, 45 were active. Of these, 27 were evaluated for inhibition of other E. coli lines, including those resistant to 6-thioguanine, 2-fluoroadenosine, 2,6-diaminopurine, or 6-mercaptopurine. Most toxic to the parent lines were 2-fluoroadenosine, 2-fluoroadenine, 2-fluoro-5'-deoxyadenosine, adenosine, 6-thioguanosine, 6-thioguanine, 6-mercaptopurine, 6-mercaptopurine ribonucleoside, 2-azaadenine, 2'-deoxyinosine, 6-N-aminoadenine, and inosine. Hypoxanthine was strongly inhibitory only to E. coli B Hill. Evidence regarding the substrate specificity of the three purine phosphoribosyltransferases was obtained by assaying for these enzymes in extracts of the various cell lines and by cross-resistance studies. The line selected for resistance to 6-thioguanine had low guanine phosphoribosyltransferase activity (guanosine monophosphate: pyrophosphate phosphoribosyltransferase, EC 2.4.2.8) and was deficient in activity for xanthine and 6-thioguanine. The lines selected for resistance to 2-fluoroadenosine and 2,6-diaminopurine were deficient in adenine phosphoribosyltransferase activity (adenosine monophosphate: pyrophosphate phosphoribosyltransferase, EC 2.4.2.7), and that selected for resistance to 6-mercaptopurine had low hypoxanthine phosphoribosyltransferase activity and undetectable activity with 6-mercaptopurine as a substrate. Purine, 6-methylpurine, 2-fluoroadenine, 2,6-diaminopurine, and 2-azaadenine were classified as adenine analogues; 6-mercaptopurine and 8-aza-2,6-diaminopurine, as hypoxanthine analogues; and 6-thioguanine and 2-amino-6-chloropurine, as analogues of guanine. The inhibition of bacterial growth by hypoxanthine, inosine, 2'-deoxyinosine, or adenosine was prevented by small amounts of thiamine or by relatively high concentrations of either cytidine or uridine. Cytidine also reversed the inhibition by some purine and purine ribonucleoside analogues. Orotate phosphoribosyltransferase (OMP: pyrophosphate phosphoribosyltransferase, EC 2.4.2.10), a possible site of action for these compounds, was not inhibited directly by the toxic agents.
Topics: Carbon Radioisotopes; Escherichia coli; Mutation; Purine Nucleosides; Purines
PubMed: 4598216
DOI: 10.1128/AAC.4.2.125 -
Chemistry (Weinheim An Der Bergstrasse,... Jul 2022The prebiotic origins of biopolymers and metabolic co-factors are key questions in Origins of Life studies. In a simple warm-little-pond model, using a drying phase to...
The prebiotic origins of biopolymers and metabolic co-factors are key questions in Origins of Life studies. In a simple warm-little-pond model, using a drying phase to produce a urea-enriched solution, we present a prebiotic synthetic path for the simultaneous formation of neopterins and tetrahydroneopterins, along with purine nucleosides. We show that, in the presence of ribose and in a formylating environment consisting of urea, ammonium formate, and water (UAFW), the formation of neopterins from pyrimidine precursors is robust, while the simultaneous formation of guanosine requires a significantly higher ribose concentration. Furthermore, these reactions provide a tetrahydropterin-pterin redox pair. This model suggests a prebiotic link in the origin of purine nucleosides and pterin cofactors that provides a possible deep prebiotic temporal connection for the emergence of nucleic acids and metabolic cofactors.
Topics: Guanine; Neopterin; Nucleosides; Purine Nucleosides; Pyrimidines; Ribose; Urea
PubMed: 35537135
DOI: 10.1002/chem.202200714 -
Bulletin Du Cancer Aug 2011Cytogenetic, molecular and phenotyping features of malignant hematologic diseases succeeded in improving their management by a more accurate stratification of patients... (Review)
Review
Cytogenetic, molecular and phenotyping features of malignant hematologic diseases succeeded in improving their management by a more accurate stratification of patients according to several groups of risk and by providing a rational for targeted therapy. Three major types of treatment (excluding cellular therapy) are currently available in onco-hematology: conventional chemotherapy, small molecules for targeted therapy and monoclonal antibodies. Conventional chemotherapy with optimization of doses and multidrug-based regimens allowed to substantially improve survival of patients and keeps a place of choice in treatment of these diseases. Targeted treatments came from the cytogenetic and molecular characterization of hemopathies. Thus, the kinase Bcr-Abl, as a result of the translocation t(9;22)(q34;q11), has been successfully targeted by tyrosine kinase inhibitors (TKI) in chronic myeloid leukemia and Ph+ acute lymphoblastic leukemia. Molecular abnormalities like internal-tandem duplication/point activating mutations in FLT3 in some acute myeloblastic leukemia or epigenetic dysregulations in some blood malignancies can also be targeted by small molecules. Hematopoietic malignant cells are phenotypically characterized by expression of cluster of differentiation (CD) on their surface. These CD are detected by flow cytometry using specific antibodies. Monoclonal antibodies targeting different CD have been developed for treatment. Rituximab, an anti-CD20 antibody, was the first monoclonal antibody successfully developed for treatment of malignant hematologic diseases. Since rituximab, many other monoclonal antibodies are being developed. Trends in malignant hematologic diseases presented here will include treatments, which have at least entered phase I/II clinical trials in adult or childhood leukemia. They include some novel drugs of conventional chemotherapy like second-generation nucleoside analogues. We will give an overview of the small molecules targeting the different cellular pathways and we will highlight those appearing as the most promising like novel TKIs. The large field of monoclonal antibodies will be also approached focusing on antibodies developed in leukemias.
Topics: Adenine Nucleotides; Antibodies, Monoclonal; Antineoplastic Agents; Arabinonucleosides; Chemistry, Pharmaceutical; Clofarabine; Hematologic Neoplasms; Humans; Molecular Targeted Therapy; Purine Nucleosides; Pyrimidinones
PubMed: 21865110
DOI: 10.1684/bdc.2011.1412