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The sequence specificity of alkylation for a series of benzoic acid mustard and imidazole-containing distamycin analogues: The importance of local sequence conformation

Wyatt, MD; Lee, M; Hartley, JA; (1997) The sequence specificity of alkylation for a series of benzoic acid mustard and imidazole-containing distamycin analogues: The importance of local sequence conformation. NUCLEIC ACIDS RES , 25 (12) 2359 - 2364. Gold open access

Abstract

The covalent sequence specificity of a series of nitrogen mustard and imidazole-containing analogues of distamycin was determined using modified sequencing techniques. The analogues tether benzoic acid mustard (BAM) and possess either one, two or three imidazole units. Examination of the alkylation specificity revealed that BAM produced guanine-N7 lesions in a pattern similar to conventional nitrogen mustards. The monoimidazole-BAM conjugate also produced guanine-N7 alkylation in a similar pattern to BAM, but at a 100-fold lower dose. The diimidazole and triimidazole conjugates did not produce detectable guanine-N7 alkylation but only alkylated at selected sites in the minor groove. Unexpectedly, the alkylation specificity at equivalent doses was nearly identical to that found for the previously reported pyrrole-BAM conjugates. The consensus sequence, 5'-TTTTGPu was strongly alkylated by the triimidazole conjugate in preference to other similar sites including three occurrences of 5'-TTTTAA. Footprinting studies were carried out to examine the non-covalent DNA binding interactions. These studies revealed that the tripyrrole-- BAM conjugate bound non-covalently to the same AT-rich sites as distamycin. In contrast, whereas the Im(3) lexitropsin bound non-covalently to GC-rich sequences, the triimidazole-BAM conjugate did not detectably footprint to either GC- or AT-rich regions at equivalent doses. The results indicate that the alkylation event is not solely dictated by the non-covalent binding and might be influenced by a unique sequence dependent conformational feature of the consensus sequence 5'-TTTTGPu.

Type: Article
Title: The sequence specificity of alkylation for a series of benzoic acid mustard and imidazole-containing distamycin analogues: The importance of local sequence conformation
Open access status: An open access publication
Publisher version: http://nar.oxfordjournals.org/
Keywords: MINOR-GROOVE, DNA-BINDING, MOLECULAR RECOGNITION, H-1-NMR SPECTROSCOPY, KINETOPLAST DNA, ADENINE-TRACT, AGENTS, CYTOTOXICITY
UCL classification: UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Cancer Institute
UCL > Provost and Vice Provost Offices > School of Life and Medical Sciences > Faculty of Medical Sciences > Cancer Institute > Research Department of Oncology
URI: http://discovery.ucl.ac.uk/id/eprint/109080
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