1. Alteration in DNA binding pattern of conformationally locked NC(O)N system: A spectroscopic investigation
- Author
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Debabrata Seth, Benjamin Kasper, Joy Debnath, Banibrata Maity, Anand Babu Velappan, and Ruel E. McKnight
- Subjects
0301 basic medicine ,Circular dichroism ,Intercalation (chemistry) ,Molecular Conformation ,Oligonucleotides ,Salt (chemistry) ,Biochemistry ,03 medical and health sciences ,0302 clinical medicine ,Structural Biology ,Animals ,Organic chemistry ,Molecular Biology ,chemistry.chemical_classification ,Quenching (fluorescence) ,Circular Dichroism ,Spectrum Analysis ,General Medicine ,Binding constant ,Fluorescence ,DNA-Binding Proteins ,Crystallography ,030104 developmental biology ,DNA Topoisomerases, Type I ,chemistry ,030220 oncology & carcinogenesis ,Excited state ,Ground state ,Protein Binding - Abstract
The binding mode of a conformationally locked NC(O)N planar system with deoxyribonucleic acid (DNA) is investigated using various spectroscopic and enzymatic assays. Compound 1 and its four different salts (comp. 2-5) were prepared for this purpose. They showed certain changes in their respective DNA-compound complex at ground state and excited state as measured by UV-vis and fluorescence emission spectra. The Stern-Volmer quenching constant (KSV) for the neutral species (1) is found 8545 M(-1), whereas, for its salts 2, 3, 4 and 5 the quenching constants were 33510 M(-1), 11352 M(-1), 19693 M(-1) and 27270 M(-1) respectively. Nevertheless, the binding constant values remain comparable in neutral and salt forms except for 5. To elucidate the reason we took their CD spectra and ran a topoisomerase I (Topo I) assay. These experimental data revel the fact that compound 1 (neutral form) binds at the minor groove of DNA, whereas, its salt (2) has an extended intercalating property.
- Published
- 2016