964-21-6Relevant articles and documents
Direct Alkylation of Deoxyguanosine by Azaserine Leads to O6-Carboxymethyldeoxyguanosine
Geisen, Susanne M.,Aloisi, Claudia M. N.,Huber, Sabrina M.,Sandell, Emma S.,Escher, Nora A.,Sturla, Shana J.
, p. 1518 - 1529 (2021/06/28)
The O6-alkylguanosine adduct O6-carboxymethyldeoxyguanosine (O6-CMdG) has been detected at elevated levels in blood and tissue samples from colorectal cancer patients and from healthy volunteers after consuming red meat. The diazo compound l-azaserine leads to the formation of O6-CMdG as well as the corresponding methyl adduct O6-methyldeoxyguanosine (O6-MedG) in cells and is therefore in wide use as a chemical probe in cellular studies concerning DNA damage and mutation. However, there remain knowledge gaps concerning the chemical basis of DNA adduct formation by l-azaserine. To characterize O6-CMdG formation by l-azaserine, we carried out a combination of chemical and enzymatic stability and reactivity studies supported by liquid chromatography tandem mass spectrometry for the simultaneous quantification of O6-CMdG and O6-MedG. We found that l-azaserine is stable under physiological and alkaline conditions as well as in active biological matrices but undergoes acid-catalyzed hydrolysis. We show, for the first time, that l-azaserine reacts directly with guanosine (dG) and oligonucleotides to form an O6-serine-CMdG (O6-Ser-CMdG) adduct. Moreover, by characterizing the reaction of dG with l-azaserine, we demonstrate that O6-Ser-CMdG forms as an intermediate that spontaneously decomposes to form O6-CMdG. Finally, we quantified levels of O6-CMdG and O6-MedG in a human cell line exposed to l-azaserine and found maximal adduct levels after 48 h. The findings of this work elucidate the chemical basis of how l-azaserine reacts with deoxyguanosine and support its use as a chemical probe for N-nitroso compound exposure in carcinogenesis research, particularly concerning the identification of pathways and factors that promote adduct formation.
NUCLEOTIDE PRODRUGS
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, (2019/07/20)
The invention relates to nucleotide prodrugs and pharmaceutical preparations thereof. The invention further relates using the prodrugs of the invention in the treatment of mitochondrial DNA (mtDNA) depletion syndrome (MDS).
Enzymatic Synthesis of Therapeutic Nucleosides using a Highly Versatile Purine Nucleoside 2’-DeoxyribosylTransferase from Trypanosoma brucei
Pérez, Elena,Sánchez-Murcia, Pedro A.,Jordaan, Justin,Blanco, María Dolores,Manche?o, José Miguel,Gago, Federico,Fernández-Lucas, Jesús
, p. 4406 - 4416 (2018/09/14)
The use of enzymes for the synthesis of nucleoside analogues offers several advantages over multistep chemical methods, including chemo-, regio- and stereoselectivity as well as milder reaction conditions. Herein, the production, characterization and utilization of a purine nucleoside 2’-deoxyribosyltransferase (PDT) from Trypanosoma brucei are reported. TbPDT is a dimer which displays not only excellent activity and stability over a broad range of temperatures (50–70 °C), pH (4–7) and ionic strength (0–500 mM NaCl) but also an unusual high stability under alkaline conditions (pH 8–10). TbPDT is shown to be proficient in the biosynthesis of numerous therapeutic nucleosides, including didanosine, vidarabine, cladribine, fludarabine and nelarabine. The structure-guided replacement of Val11 with either Ala or Ser resulted in variants with 2.8-fold greater activity. TbPDT was also covalently immobilized on glutaraldehyde-activated magnetic microspheres. MTbPDT3 was selected as the best derivative (4200 IU/g, activity recovery of 22 %), and could be easily recaptured and recycled for >25 reactions with negligible loss of activity. Finally, MTbPDT3 was successfully employed in the expedient synthesis of several nucleoside analogues. Taken together, our results support the notion that TbPDT has good potential as an industrial biocatalyst for the synthesis of a wide range of therapeutic nucleosides through an efficient and environmentally friendly methodology.
Functionalization of Guanosine and 2′-Deoxyguanosine at C6: A Modified Appel Process and SNAr Displacement of Imidazole
Janeba, Zlatko,Lin, Xiaoyu,Robins, Morris J.
, p. 137 - 147 (2007/10/03)
Treatment of sugar-protected 2-N-trityl derivatives of guanosine and 2′-deoxyguanosine with imidazole/triphenylphosphine/iodine/ethyldiisopropylamine gives the corresponding 6-(imidazol-1-yl)-2-(tritylamino)purine nucleosides. S NAr displacement of the imidazole moiety with nucleophiles provides 2-amino-6-substituted-purine nucleosides and 2′-deoxynucleosides.
Synthesis and characterization of DNA containing O6-carboxymethylguanine
Xu, Yao-Zhong
, p. 6075 - 6081 (2007/10/03)
O6-Carboxymethylguanine was formed in DNA treated with N-nitrosoglycocholic acid and believed to be implicated in human gastrointestinal and colorectal tumour. An efficient method is presented here for synthesis of oligodeoxynucleotides containing O6-carboxy-methylguanine at pre-determined positions. The synthetic protocol also allows for production of oligomers containing O6-aminocarbonyl-methylguanine. These guanine-modified oligomers have been fully characterized and could provide a useful tool for biological studies of these modified bases. (C) 2000 Elsevier Science Ltd.
The mechanism of decomposition of N-methyl-N-nitrosourea (MNU) in water and a study of its reactions with 2'-deoxyguanosine, 2'-deoxyguanosine 5'-monophosphate and d(GTGCAC)
Golding, Bernard T.,Bleasdale, Christine,McGinnis, Joseph,Mueller, Susanna,Rees, Hue Thu,Rees, Nicholas H.,Farmer, Peter B.,Watson, William P.
, p. 4063 - 4082 (2007/10/03)
The carcinogenicity of N-methyl-N-nitrosourea (MNU) arises, from its ability to methylate DNA, This occurs in an aqueous environment and therefore an appreciation of the mode of decomposition of MNU in water is essential to understanding the mechanism of DNA methylation and its base sequence dependence. The kinetics of MNU hydrolyses are shown to be first order in MNU with a steep rise in rate above pH 8. Using NMR for in situ monitoring of reaction intermediates and products from hydrolyses of [13CO]MNU, [15NH2]MNU and [13CH3]MNU, it is proved that base-induced hydrolysis of MNU is initiated by deprotonation at the carbamoyl group. The critical reactive species are shown to be the methyldiazonium ion (Me-N2+) and cyanate (NCO-). Investigations of reactions of [13CH3]MNU with 2'-deoxyguanosine (dGuo) and 2-deoxyguanosine 5'-monophosphate (dGuo-5P) showed that: a) the site of methylation of dGuo is highly pH-dependent (relatively more N-1 and O6-methylation compared to N-7 occurs at higher pH; b) the principal site of methylation of dGuo-5P by MNU is at phosphate; c) incorporation of deuterium into methyl groups occurs in D2O at higher pH. Methylation of the oligonucleotide d(GT[15N]GCAC) by MNU in D2O showed partial deuteriation of the N7-methyl groups of the guanines, whilst methylation by MNU in water indicated no significant preference for either guanine with respect to N7-methylation.
N7-DNA: Synthesis and base pairing of oligonucleotides containing N7-(2-deoxy-β-D-erythro-pentofuranosyl)guanine (N7G(d))
Seela,Leonard
, p. 477 - 487 (2007/10/03)
The synthesis of oligonucleotides containing N7-(2-deoxy-β-D-erythro-pentofuranosyl)guanine (N7G(d); 1) is described. Compound 1 was prepared by nucleobase-anion glycosylation of 2-amino-6-methoxypurine (5) with 2-deoxy-3,5-di-O-(4-toluoyl)-α-D-erythro-pentofuranosyl chloride (6) followed by detoluoylation and displacement of the MeO group (8 → 10 → 1). Upon base protection with the (dimethylamino)methylidene residue (→ 11) the 4,4-dimethoxytrityl group was introduced at OH-C(5') (→ 12). The phosphonate 3 and the phosphoramidite 4 were prepared and used in solid-phase oligonucleotide synthesis. The self-complementary dodecamer d(N7G-C)6 shows sigmoidal melting. The T(m) of the duplex is 40°. This demonstrates that guanine residues linked via N(7) of purine to the phosphodiester backbone are able to undergo base pairing with cytosine.
The in vitro methylation of DNA by a minor groove binding methyl sulfonate ester
Encell,Shuker,Foiles,Gold
, p. 563 - 567 (2007/10/03)
The preparation of sequence and groove specific DNA methylating agents based on N-methylpyrrolecarboxamide subunits appended with an O-methyl sulfonate ester functionality (MeOSO2(CH2)2-Lex) has previously been described [Zhang, Y., Chen, F.-X., Mehta, P., and Gold, B. (1993) Biochemistry 32, 7954-7965]. In contrast to simple methyl sulfonate esters, e.g., methyl methanesulfonate (MMS), which predominantly methylate at 7- guanine, MeOSO2(CH2)2-Lex affords N3-methyladenine (3-MeAde) as its major adduct. Using competitive ELISA determinations, the methylation at major and minor groove sites in calf thymus DNA by MeOSO2(CH2)2-Lex has been precisely quantitated. The yields of N7-methylguanine (7-MeGua), 3-MeAde, and O6-methyldeoxyguanosine (6-Me-dGuo) are 0.424, 3.195, and 0.0027 mmol of adduct/mol of DNA, respectively, using 10 μM MeOSO2(CH2)2-Lex and 100 μM DNA. This compares to 0.773, 0.072, and 0.0033 mmol of adduct/mol of DNA for 7-MeGua, 3-MeAde, and 6-Me-dGuo, respectively, using MMS. The increase in the yield of 3-MeAde due to the minor groove equilibrium binding properties of MeOSO2(CH2)2-Lex is ~40-fold relative to MMS.
6-O-substituted guanosine derivatives
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, (2008/06/13)
The following species of N6-activated guanosine derivatives are disclosed: 2-N-trifluoroacetamido-6-(4-nitrophenoxy)-9-(2-deoxy-beta-D-erythro-pentofuranosyl)purine 2-N-trifluoroacetamido-6-pentafluorophenoxy-9-(2-deoxy-beta-D-erythro-pentofuranosyl)purine 6-dimethylpyridinium-9-(2-deoxy-beta-D-erythropentofuranosyl)purine These guanosine compounds are useful as precursors in the synthesis of a wide variety of antiviral and anticancer nucleosides such as 2-amino-2-deoxyadenosine or 6-thio-deoxyguanosine. Also disclosed are oligonucleotides containing the above nucleosides which are precursors to modified oligonucleotides which are useful as hybridization probes.
Deacylation of 2-N-Isobutyryl- and 2-N-Isobutyryl-6-O-methyl-2'-deoxyguanosine in the Condensed and Gas Phase. A Kinetic Investigation
Liguori, Angelo,Napoli, Anna,Siciliano, Carlo,Sindona, Giovanni
, p. 1833 - 1838 (2007/10/02)
The kinetics of deacyclation of 2-N-isobutyryl- 2 and 2-N-isobutyryl-6-O-methyl-2'-deoxyguanosine 4 show that the former can be deblocked by ammonolysis, whereas the latter requires strong alkaline conditions.This different behaviour is correlated with the availability of the enolizable lactam function of the guanine ring.Similar effects are in operation in the unimolecular gas-phase dissociations of the same species.
