Laurence Hurley

PMID: 2966637;Abstract:

The recognition and repair of the helix-stabilizing and relatively nondistortive CC-1065-(N3-adenine)-DNA adduct by UVRABC nuclease has been investigated both in vivo with ΦX174 RFI DNA by a transfection assay and in vitro by a site-directed adduct in a 117 base pair fragment from M13mpl. CC-1065 is a potent antitumor antibiotic produced by Streptomyces zelensis which binds within the minor groove of DNA through N3 of adenine. In contrast to the helix-destabilizing and distortive modifications of DNA caused by ultraviolet light or N-acetoxy-2-(acetylamino)fluorene, CC-1065 increases the melting point of DNA and decreases the S1 nuclease activity. Using a viral DNA-Escherichia coli transfection system, we have found that the uvrA, uvrB, and uvrC genes, which code for the major excision repair proteins for UV- and NAAAF-induced DNA damage, are also involved in the repair of CC-1065-DNA adducts. In contrast, the uvrD gene product, which has been found to be involved in the repair of UV damage, has no effect in repairing CC-1065-DNA adducts. Purified UVRA, UVRB, and UVRC proteins must work in concert to incise the drug-modified ΦX174 RFI DNA. Using a site-directed and multiple CC-1065 modified (MspI-BstNI) 117 base pair fragment from M13mpl, we have found that UVRABC nuclease incises at the eighth phosphodiester bond on the 5′ side of the CC-1065-DNA adduct on the drug-modified strand. The enzymes do not cut the noncovalently modified strand. At low drug binding ratios, of the four CC-1065 binding sites identified in the (MspI-BstNI) 117 base pair fragment, GATTA*, GGAAA*, GATAA*, and TTTTA* (* indicates the covalently modified adenine), only the adduct at the high-affinity binding site, GATTA*, is incised by the UVRABC nucleases. No difference in the effect of CC-1065 on local DNA structure, as determined by the DNase I cleavage pattern, was evident among these sites. At high drug binding ratios, a fifth drug binding site, AGCTA*, is identified. At this concentration UVRABC nucleases are unable to incise any of these five CC-1065-DNA adducts. The DNA sequence and/or helix-stabilizing effect of multiple adducts may determine the recognition and/or incision of the drug-DNA adduct by UVRABC nuclease. These results are discussed in relation to the structure of the CC-1065-DNA adduct and the effect of drug binding on local DNA structure. © 1988 American Chemical Society.

PMID: 15379535;Abstract:

Rotational-echo double resonance solid-state ³¹P{¹⁹F} and ¹³C{¹⁹F} NMR spectra have been used to locate the binding of a fluoroquinobenzoxazine to a DNA G-quadruplex labeled by phosphorothioation and [methyl-¹³C]thymidine.

PMID: 354779;Abstract:

Anthramycin, one of the pyrrolo(1,4)benzodiazepine antibiotics with potent antitumor activity, was tested for its effects on a number of genetic parameters. The results show that this antibiotic is nonmutagenic in the Ames strains of Salmonella typhimurium while mutagenic in only one and antimutagenic in the rest of the genes tested in the eukaryotic organism Saccharomyces cerevisiae. The antibiotic is, however, a potent recombinogen in as much as it reduced mitotic crossing over, mitotic gene conversion, and possibly other chromosomal alterations in a diploid strain of S. cerevisiae. These studies emphasize the need for a battery of test systems including eukaryotic organisms to detect the genetic activity of certain antitumor drugs. The importance of considering data distinguishing between highly mutagenic and poorly mutagenic cancer chemotherapeutic agents is also discussed.