A facile method for the introduction of various substituents at the C-6 position of guanosine and 2'-deoxyguanosine is reported. In a simple, 1-step transformation, tert-butyldimethylsilyl protected guanosine and 2'-deoxyguanosine were converted to the O(6)-(benzotriazol-1-yl) derivatives via reaction with 1H-benzotriazol-1-yloxy-tris(dimethylamino)phosphonium hexafluorophosphate (BOP) and 1,8-...

The chemical syntheses of RNA oligomers containing modifications on the 5'-carbon of the 5'-terminal nucleoside for crystallographic and mechanistic studies of the hairpin ribozyme are reported. Phosphoramidites 4 and 8 were prepared and used in solid phase syntheses of RNA oligomers containing the sequence 5'-N'UCCUCUCC, where N' indicates either 5'-chloro-5'-deoxyguanosine or 5'-amino-5'-deox...

The base moieties of DNA precursors in the nucleotide pool are subjected to oxidative damage, and the formation of damaged DNA precursors is an important source of mutagenesis. 8-Hydroxy-2'-deoxyguanosine 5'-triphosphate, also known by the name of its keto-enol tautomer as 8-oxo-7,8-dihydro-2'-deoxyguanosine 5'-triphosphate, and 2-hydroxy-2'-deoxyadenosine 5'-triphosphate have been identified a...

Covalent binding of the benzo[a]pyrene metabolite (+/-)7beta,8alpha-dihydroxy-9alpha,10alpha-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene to calf thymus DNA was investigated. Enzymatic hydrolysis of the carcinogen-modified DNA and subsequent separation via reversed-phase high-pressure liquid chromatography resulted in the detection and isolation of seven distinct products. High-resolution mass spect...

We present here the first mass spectroscopic (MS) identification of the main tamoxifen-induced DNA adducts in rat liver. The two main adducts were isolated by high-performance liquid chromatography (HPLC) and identified by MS, MS-MS and ultraviolet spectroscopy. Adduct 1 was the N-desmethyltamoxifen-deoxyguanosine adduct in which the alpha-position of the metabolite N-desmethyltamoxifen is link...

The hydrogen-bonded guanine tetrad, or G-quartet has been implicated in a variety of biological roles, including the function of chromosome telomeres. Here effect of the hydroxylation of guanosine at the 8 position on the G-quartet formation was examined. Electrospray inonization mass (ESI-MS) spectra of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) and 2'-deoxyguanosine (dG) were measured in o...

Biochemical, biophysical and biological studies of oligonucleotides containing lesions at defined sites provide a molecular basis for the effects of DNA lesions. dG (deoxyguanosine) is the most easily oxidized of the four native nucleotides. The chemical reactivity of dG correlates with compilations of mutations, which reveal that a significant fraction of transitions or transversions involve d...

High-quality Raman spectra have been collected on single DNA crystals kept at 100 K in a flow of cold nitrogen gas prior, during and after macromolecular crystallography (MX) data collection. The non-symmetric bending vibration for C-Br bonds in 8-bromo-2'-deoxyguanosine has been unambiguously identified at 293 cm(-1) in the non-resonant Raman spectra. The breakage of this bond could be monitor...