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The interaction of anti-tumour drugs with reconstituted chromatin has been investigated using defined nucleosomal complexes. This allowed the effect of nucleosome cores on drug-induced DNA damage to be assessed for four nitrogen mustard analogues, dimethylsulphate and three cisplatin analogues. A defined nucleosomal complex was employed that contained two precisely positioned nucleosome cores. The construct was then subjected to drug treatment, and the resulting DNA damage was quantitatively analysed using a Taq DNA polymerase stop assay. At the sites of damage, densitometric comparisons between purified and reconstituted DNA were used to evaluate the influence of nucleosomal core proteins on specific drug–DNA interactions. Results were combined with previous data obtained for other DNA-damaging drugs investigated using the same nucleosomal construct. For most of the DNA-damaging agents studied, this method revealed protection at the positioned nucleosome cores and indicated that the preferred site of DNA binding for these compounds was in the linker region of the construct. Statistical analyses confirmed the significant level of damage protection conferred by the nucleosome cores and revealed differences between the examined compounds. Larger compounds generally displayed a greater tendency to target the linker region of the nucleosomal DNA and were impeded from damaging nucleosomal core DNA. In contrast, smaller molecules had greater access to nucleosomal core DNA. [ABSTRACT FROM AUTHOR]

In this review, the use of automated DNA sequencing techniques to determine the sequence specificity of compounds that interact with DNA is discussed. The sequence specificity of a DNA-damaging agent is an essential element in determining the cellular mechanism of action of a drug. A number of DNA-damaging compounds are mutagenic, carcinogenic, as well as being widely used as cancer chemotherapeutic agents. The distribution of lesions in a sequence of DNA can give vital clues in the determination of the precise mechanism of interaction of the agent with DNA. The DNA sequence specificity of a number of DNA-damaging agents has been delineated using automated DNA sequencing technology, and these studies are discussed in this review. The current state-of-the-art methodology involves capillary electrophoresis with laser-induced fluorescence detection usually on an Applied Biosystems ABI 3730 capillary sequencer. This current technique has higher resolution, greater sensitivity, higher precision, more rapid separation times, is safer and easier to perform than previous methods. The two main methods to determine the DNA sequence selectivity of compounds that interact with DNA are described: end labelling and the polymerase stop assay. The interaction of the antitumour drug, bleomycin, with DNA is utilized to illustrate the recent technological advances. [ABSTRACT FROM AUTHOR]

The stereochemistry of the title compound, C19H21N3, has been confirmed by a single-crystal X-ray analysis. The bicyclic ring system adopts a cis-deca­lin-like conformation, which presumably minimizes steric repulsion involving the bridgehead phenyl substituent. The conformation of the amino group appears to be dictated by a nitro­gen anomeric effect. [ABSTRACT FROM AUTHOR]