961-07-9Relevant articles and documents
Highly sequence selective photoreaction of 5-bromouracil-containing deoxyhexanucleotides
Sugiyama, Hiroshi,Tsutsumi, Yasushi,Saito, Isao
, p. 6720 - 6721 (1990)
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Chemical composition and toxicity of Taiwanese betel quid extract
Wang,Su,Lii
, p. 135 - 144 (1999)
In this genotoxic study, the Ames Salmonella microsome test showed that an aqueous extract of betel quid did not induce mutagenicity in Salmonella typhimurium strains TA98 and TA100. Mammalian cell studies (Chinese hamster ovary K1 cell; CHO-K1 cell) revealed that only higher concentrations (100 and 1000μg/ml) of aqueous extract weekly increased the frequencies of sister-chromatid exchange (SCE) in the absence of S9. Animal (male Sprague-Dawley rat) studies showed that low-dose feeding (0.53g dry aqueous extract/kg diet) significantly increased the activities of glutathione (GSH) peroxidase and cytoplasmic glutathione S-transferase (cGST) of liver, high-dose feeding (26.5g dry aqueous extract/kg diet) lowered the contents of GSH and total glutathione. The effect of an aqueous extract of betel quid on the oxidation of 2'-deoxyguanosine (2'-dG) to 8-hydroxy-2'-deoxyguanosine (8-OH-dG) evaluated that this aqueous extract may act as a pro-oxidant at lower dosage and may be dependent on the iron ions in the model system. However, the aqueous extract of betel quid showed antioxidant activity at higher doses by the ability of the scavenging effect of the hydroxyl radicals. Copyright (C) 1999 Elsevier Science B.V.
Independent Generation and Reactivity of 2′-Deoxyguanosin- N1-yl Radical
Zheng, Liwei,Greenberg, Marc M.
, p. 8665 - 8672 (2020/07/03)
2′-Deoxyguanosin-N1-yl radical (dG(N1-H)?) is the thermodynamically favored one-electron oxidation product of 2′-deoxyguanosine (dG), the most readily oxidized native nucleoside. dG(N1-H)? is produced by the formal dehydration of a hydroxyl radical adduct of dG as well as by deprotonation of the corresponding radical cation. dG(N1-H)? were formed as a result of the indirect and direct effects of ionizing radiation, among other DNA damaging agents. dG(N1-H)? was generated photochemically (λmax = 350 nm) from an N-aryloxy-naphthalimide precursor (3). The quantum yield for photochemical conversion of 3 is ~0.03 and decreases significantly in the presence O2, suggesting that bond scission occurs from a triplet excited state. dG is formed quantitatively in the presence of excess β-mercaptoethanol. In the absence of a reducing agent, dG(N1-H)? oxidizes 3, decreasing the dG yield to ~50%. Addition of 8-oxo-7,8-dihydro-2′-deoxyguanosine (8-oxodGuo) as a sacrificial reductant results in a quantitative yield of dG and two-electron oxidation products of 8-oxodGuo. N-Aryloxy-naphthalimide 3 is an efficient and high-yielding photochemical precursor of dG(N1-H)? that will facilitate mechanistic studies on the reactivity of this important reactive intermediate involved in DNA damage.
Solid-phase synthesis and structural characterisation of phosphoroselenolate-modified DNA: A backbone analogue which does not impose conformational bias and facilitates SAD X-ray crystallography
Conlon, Patrick F.,Eguaogie, Olga,Wilson, Jordan J.,Sweet, Jamie S. T.,Steinhoegl, Julian,Englert, Klaudia,Hancox, Oliver G. A.,Law, Christopher J.,Allman, Sarah A.,Tucker, James H. R.,Hall, James P.,Vyle, Joseph S.
, p. 10948 - 10957 (2019/12/23)
Oligodeoxynucleotides incorporating internucleotide phosphoroselenolate linkages have been prepared under solid-phase synthesis conditions using dimer phosphoramidites. These dimers were constructed following the high yielding Michaelis-Arbuzov (M-A) reaction of nucleoside H-phosphonate derivatives with 5′-deoxythymidine-5′-selenocyanate and subsequent phosphitylation. Efficient coupling of the dimer phosphoramidites to solid-supported substrates was observed under both manual and automated conditions and required only minor modifications to the standard DNA synthesis cycle. In a further demonstration of the utility of M-A chemistry, the support-bound selenonucleoside was reacted with an H-phosphonate and then chain extended using phosphoramidite chemistry. Following initial unmasking of methyl-protected phosphoroselenolate diesters, pure oligodeoxynucleotides were isolated using standard deprotection and purification procedures and subsequently characterised by mass spectrometry and circular dichroism. The CD spectra of both modified and native duplexes derived from self-complementary sequences with A-form, B-form or mixed conformational preferences were essentially superimposable. These sequences were also used to study the effect of the modification upon duplex stability which showed context-dependent destabilisation (-0.4 to-3.1 °C per phosphoroselenolate) when introduced at the 5′-Termini of A-form or mixed duplexes or at juxtaposed central loci within a B-form duplex (-1.0 °C per modification). As found with other nucleic acids incorporating selenium, expeditious crystallisation of a modified decanucleotide A-form duplex was observed and the structure solved to a resolution of 1.45 ?. The DNA structure adjacent to the modification was not significantly perturbed. The phosphoroselenolate linkage was found to impart resistance to nuclease activity.