The binding of bis(1,10-phenanthroline)Cu(I)$\sp{+}$, Phen$\sb2$Cu$\sp{+}$, to DNA was investigated. Biochemical and physical techniques were employed to determine (1) the sequence preferences for binding, (2) the properties of the DNA macromolecule responsible for the binding preferences, and (3) the equilibrium binding constant and the mode of binding. / Binding specificity was primarily at the level of triplets and quartets. The trimer TAT was consistently the most preferred sequence with strong cleavage occurring at the central adenosine. The trimer, TGT, and the tetramer sequences, TAGT, CAGT, and TAAT, were moderately to strongly preferred. Preferential cleavage was also observed for the pentamer CAAGC. / An oligonucleotide duplex containing TAT was strongly cleaved at the central adenosine. Duplexes containing C(:G)AT, TGT, TAC(:G), and TAC(:I) all showed significantly reduced cleavage. Duplexes containing C(:I)AT and TIT were cleaved at level nearly equivalent to that for the TAT duplex. These results support a favored intercalation site at TA steps as the primary determinant of Phen$\sb2$Cu$\sp{+}$ preferential binding with inhibition arising due to guanine amino groups in the minor groove. / The mono-complex, PhenCu$\sp{+}$, preferentially cleaved at CG sequences and not at TA sequences, indicating a crucial role in specificity determination for the non-intercalated phenanthroline. Inhibition of cleavage by guanine 2-amino groups can then be attributed to unfavorable contacts with the protons at the 2 and 9 positions of the non-intercalated phenanthroline. / An induced, conservative circular dichroism spectrum and increases in the viscosity of DNA solutions upon addition of Phen$\sb2$Cu$\sp{+}$ confirmed intercalation as the mode of binding. From visible spectroscopy studies an equilibrium binding constant on the order of 10$\sp4$ at 0.2 M ionic strength was determined. Binding was observed to be positively cooperative and dependent upon the concentration of uncomplexed phenanthroline in solution. Cooperative binding can be attributed to the need to distort the complex from its preferred geometry upon intercalation with subsequent favorable structural rearrangement of the DNA helix after binding. / Source: Dissertation Abstracts International, Volume: 51-01, Section: B, page: 0195. / Major Professor: Randolph L. Rill. / Thesis (Ph.D.)--The Florida State University, 1989.
| Identifer | oai:union.ndltd.org:fsu.edu/oai:fsu.digital.flvc.org:fsu_78162 |
| Contributors | Veal, James Marvin., Florida State University |
| Source Sets | Florida State University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | 192 p. |
| Rights | On campus use only. |
| Relation | Dissertation Abstracts International |
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