Synthesis and application of fluorescent labeled nucleotides to assay DNA damage.

A facile method was developed to covalently attach a fluorophore to the 5'-phosphate of a nucleic acid. The procedure, illustrated by coupling 5'-dNmp (N = A,C,G,T) with 5-dimethylaminonaphthalene 1-sulfonyl chloride, commonly known as Dansyl chloride, involves 5'-phosphoramidation with ethylenediamine (EDA) followed by conjugation of the free aliphatic amino group of the phosphoramidate with Dansyl chloride. This method is also applicable to multi-incorporation of fluorescent labels in the nucleic acids.

13C- and 31P-NMR studies of the conformation of carcinogen-modified nucleic acid dimers.

The effect of the carcinogen acetylaminofluorene (AAF) on nucleic acid structure was examined using 13C- and 31P-NMR spectroscopies. Conformational effects were compared in two AAF-modified dinucleoside monophosphates (ApG and GpA) and two AAF-modified deoxydinucleotides (dpApG and dpGpA). Changes in adenine 13C chemical shifts on formation of the AAF-adduct and as a function of temperature provided evidence of base stacking.

13C-NMR studies of the effects of the carcinogen acetylaminofluorene on the conformation of dinucleoside monophosphate.

13C-NMR spectra are obtained in aqueous solution of dinucleoside monophosphates (ApG and GpA) and of their adducts formed by the addition of the carcinogen acetylaminofluorene (AAF) to the C8 position of the guanine. The base and sugar carbons of all dimers and adducts are assigned. The task of assigning base and carbohydrate resonances was accomplished using a series of reference compounds.

13C nuclear magnetic resonance studies of radiation damage: radiation-induced degradation of glycine.

The stable products generated in polycrystalline glycine exposed to ionizing radiation and subsequently dissolved in water were identified by using (13)C nuclear magnetic resonance spectroscopy. The study was done on isotopically enriched samples. The results can be correlated with the results of many other studies on irradiated glycine using other methods.