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- Doglia, S. M., et al.
(författare)
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QUINACRINE - SPECTROSCOPIC PROPERTIES AND INTERACTIONS WITH POLYNUCLEOTIDES
- 1993
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Ingår i: Biopolymers. - : Wiley. - 0006-3525 .- 1097-0282. ; 33:9, s. 1431-1442
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Tidskriftsartikel (refereegranskat)abstract
- The acridine dye quinacrine and its interactions with calf thymus DNA, poly(dA-dT).poly(dA-dT), and poly(dG-dC).poly(dG-dC) were studied by light absorption, linear dichroism, and fluorescence spectroscopy. The transition moments of quinacrine give rise to absorption bands polarized along the short axis (400-480-nm band), and the long axis (345-nm and 290-nm bands) of the molecule, respectively. Linear dichroism studies show that quinacrine intercalates into calf thymus DNA as well as into the polynucleotides, displaying fairly homogeneous binding to poly (dA-dT).poly(dA-dT), but more than one type of intercalation site for calf thymus DNA and poly(dG-dC).poly(dG-dC). Fluorescence spectroscopy shows that for free quinacrine the pK = 8.1 between the mono- and diprotonated states also remains unchanged in the excited state. Quinacrine bound to calf thymus DNA and polynucleotides exhibits light absorption typical for the intercalated diprotonated form. The fluorescence enhancement of quinacrine bound to poly (dA-dT).poly(dA-dT) may be due to shielding from water interactions involving transient H-bond formation. The fluorescence quenching in poly (dG-dC).poly (dG-dC) may be due to excited state electron transfer from guanine to quinacrine. (C) 1993 John Wiley & Sons, Inc.
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| 2. |
- Eriksson, M., et al.
(författare)
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BINDING OF DELTA- RU(PHEN)(3) (2+) AND LAMBDA- RU(PHEN)(3) (2+) TO D(CGCGATCGCG) (2) STUDIED BY NMR
- 1994
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 1520-4995 .- 0006-2960. ; 33:17, s. 5031-5040
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Tidskriftsartikel (refereegranskat)abstract
- The interactions of the Delta and Delta enantiomers of the chiral metal complex [Ru(phen)(3)](2+) (phen = 1,10-phenanthroline) with the oligonucleotide duplex [d(CGCGATCGCG)](2) have been studied with NMR and CD spectroscopy. From NOESY data it is shown that the interaction primarily takes place in the minor groove of the oligonucleotide which remains in a B-like conformation. The observed NOEs also provide evidence that the metal complexes preferentially bind to the central AT region. The observed AT specificity is more pronounced with the Delta as compared to the Delta enantiomer, which interacts with a larger part of the oligonucleotide. Furthermore, the NOESY data show that neither of the enantiomers binds by classical intercalation. This is also supported by a comparison study of the analogue [Ru(phen)(2)DPPZ](2+) (DPPZ = dipyrido[ 3,2-a:2',3'-c] phenazine) which intercalates in DNA. The NMR as well as the CD results show that the Delta and Delta enantiomers of [Ru(phen)(3)](2+) bind in different modes to [d(CGCGATCGCG)](2). Comparison of CD spectra of the metal complex in the presence of [d(CGCGATCGCG)](2), poly(dAdT).poly(dAdT), poly(dGdC).poly(dGdC), and calf thymus DNA suggests that these binding modes are independent of DNA sequence. The results are found to be compatible with binding of Delta-[Ru(phen)(3)](2+) by insertion of two phenanthroline ligands into the minor groove, causing minor distortions of the DNA structure, whereas the Delta enantiomer binds in a mode that leaves the DNA structure unaffected.
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| 3. |
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| 4. |
- Hiort, Catharina, 1962, et al.
(författare)
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DNA-BINDING OF DELTA- RU(PHEN)2DPPZ 2+ AND LAMBDA- RU(PHEN)2DPPZ 2
- 1993
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 115:9, s. 3448-3454
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Tidskriftsartikel (refereegranskat)abstract
- Linear dichroism (LD) spectroscopy and steady-state as well as time-resolved luminescence spectroscopy have been used to investigate the interaction of the DELTA and LAMBDA enantiomers of Ru(phen)2DPPZ2+ (phen = 1,10-phenanthroline; DPPZ = dipyrido[3,2-a:2',3'-c]phenazine) with DNA. The pure enantiomers, which were difficult to separate by traditional resolving methods, were synthesized via a chiral precursor. Changes in luminescence, isotropic absorption and excited state lifetimes upon binding, and the LD observed in flow-oriented DNA systems provide detailed information about the DNA binding of the enantiomers. Flow LD shows that both enantiomers bind to DNA in a well-defined manner with an orientation of the dipyridophenazine chromophore consistent with intercalation of this moiety between base-pairs. Both enantiomers are found to show luminescence in the presence of DNA to which they bind very strongly (K almost-equal-to 10(8) M-1); however, the relative luminescence quantum yield of the bound DELTA enantiomer is 6-10 times larger than that of the bound LAMBDA enantiomer. Furthermore, for each enantiomer two distinct excited state lifetimes are found in varying proportions depending on the binding ratio. The large difference in luminescence quantum yield between the enantiomers is interpreted in terms of slightly different intercalation geometries of the dipyridophenazine ligand, resulting in different protections from quenching by solvent water and diastereomeric differences in the interactions between enantiomers bound in contigue on DNA.
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| 5. |
- Hiort, Catharina, 1962
(författare)
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DNA Binding of Metal Complexes. A Spectroscopic Study of Trigonal Ru(II)phenanthroline Complexes and Uranyl(VI) Ion with Respect to Specific Interactions with DNA
- 1992
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The interaction of metal complexes with nucleic acids has attracted attention owing to their potentials as optical probes, probes of chirality, and for use as artificial restriction enzymes. To understand the underlying mechanisms in these contexts we studied the binding to DNA of the enantiomers of two chiral ruthenium(II) metal complexes ([Ru(phen)3]2+ and [Ru(phen)2]2+DPPZ) phen=1,10-phenanthroline, DPPZ=dipyrido[3,2-a:2',3'-c]phenazine, and of the linear uranium(VI) complex, uranyl ([UO2]2+), using linear dichroism, circular dichroism and luminescence, as well as nuclear magnetic resonance spectroscopy. For the first metal complex, [Ru(phen)3]2+, both enantiomers (D and L) were found to bind weakly and non-intercalatively in the minor groove of B-form DNA. Each enantiomer exhibits its own unique binding geometry independent of DNA base sequence. Binding affinities, however, vary slightly with base composition. Upon binding, the D enantiomer considerably decreases the flow orientation of DNA due to shortened persistence length. The complex was shown to be unsuitable for probing DNA handedness, since it induces B conformation in Z form DNA. Both D and L of [Ru(phen)2DPPZ]2+ were found to bind strongly (K*108 M-1), and with very similar binding geometries in which the DPPZ wing intercalates between DNA base pairs. However, it is the D enantiomer that is mainly responsible for the luminescence enhancement observed for the racemate. We explain this difference in terms of a slight variation in binding geometry and packing on DNA, giving better access to quenching solvent water in the L complex. Uranyl was shown to bind very strongly to DNA (K*1010 M-1), and drastically affect its hydrodynamical behaviour. We suggest that uranyl binds in the minor groove, probably by coordination of phosphate oxygens by uranium. The LD data is consistent with an orientation in which the long axis of uranyl lies along the groove. Binding is shown to be a prerequisite for uranyl-mediated photocleavage of DNA.
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| 6. |
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| 8. |
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| 9. |
- Nielsen, P. E., et al.
(författare)
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DNA-BINDING AND PHOTOCLEAVAGE BY URANYL(VI) (UO2(2+)) SALTS
- 1992
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 1520-5126 .- 0002-7863. ; 114:13, s. 4967-4975
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Tidskriftsartikel (refereegranskat)abstract
- The interaction of the uranyl(VI) ion (UO22+) with DNA and its light-induced cleavage of DNA has been studied using flow-linear dichroism and P-32-endlabeled oligonucleotides. It was found that binding of uranyl ion to DNA is a prerequisite for photocleavage; from run-off experiments the binding constant was estimated to be of the order of 10(10) M-1 at pH 4. The angular orientation of the [O=U=O]2+ chromophore is consistent with binding by bridging phosphate groups on opposite strands of the minor groove of DNA; at higher DNA concentration aggregation indicates intermolecular bridging as well. The uranyl-mediated photocleavage of DNA is not influenced by the presence of O2, is more efficient at low pH (
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| 10. |
- Nordén, Bengt, 1945, et al.
(författare)
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DNA INTERACTION WITH CHIRAL METAL-COMPLEXES
- 1991
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Ingår i: Nucleosides and Nucleotides. - : Informa UK Limited. - 0732-8311 .- 1532-2335. ; 10:1-3, s. 195-205
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Tidskriftsartikel (refereegranskat)abstract
- Despite extensive study of DNA interaction with propeller-shaped metal complexes, such as the DELTA and LAMBDA enantiomers of [Ru(1,10-phenanthroline)3]2+, the basis for their enantioselectivity, and even their binding modes, are not yet fully understood. H-1 NMR studies of the interactions with the self-complementary oligonucleotide d(CGCGATCGCG)2 indicate that both enantiomers bind into the minor groove of the central AT-TA region, but with a rapid exchange between the bound and free states. Flow linear dichroism (FLD) and circular dichroism (CD) show different binding geometries for the two enantiomers. These two geometries are found in natural DNA as well as in a number of different B form polynucleotides, virtually independent of base composition and of methylation. The DNA interaction with the [Ru(1,10-phenanthroline)3]2+ complexes will be reconsidered in the light of NMR, FLD, CD and fluorescence results.
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