Effect of Number and Position of Positive Charges on the Stacking of Porphyrins along Poly[d(A-T)(2)] at High Binding Densities

Title
Effect of Number and Position of Positive Charges on the Stacking of Porphyrins along Poly[d(A-T)(2)] at High Binding Densities
Author(s)
정진아[정진아]이상화[이상화]김표[김표]손영구김석규
Keywords
CIRCULAR-DICHROISM; SUPRAMOLECULAR ASSEMBLIES; DNA INTERACTIONS; NUCLEIC-ACIDS; MESO-TETRAKIS(N-METHYLPYRIDINIUM-4-YL)PORPHYRIN; LIGHT; OLIGONUCLEOTIDES; MESO-TETRAKIS(3-N-METHYLPYRIDINIUMYL)PORPHYRIN; INTERCALATION; INDUCTION
Issue Date
201006
Publisher
AMER CHEMICAL SOC
Citation
JOURNAL OF PHYSICAL CHEMISTRY B, v.114, no.22, pp.7641 - 7648
Abstract
At high porphyrin densities, the effects of the number and position of the positive charges of the periphery ring on the stacking of the porphyrin on poly[d(A-T)(2)] was investigated using polarized spectroscopy, including circular and linear dichroism (CD and LD, respectively). The CD spectrum of meso-tetrakis(N-methylpyridinium-4-yl)porphyrin(TMPyP) consisted of two positive bands in the Soret absorption region at low [porphyrin]/[DNA base] ratios (R ratios) and changed to two distinguishable categories of the bisignate CD spectrum with increasing R ratio. These CD spectra were attributed to the monomeric groove binding, and the moderately and extensively stacked TMPyPs. In contrast, trans-bis(N-methylpyridinium-4-yl)porphyrin (trans-BMPyP) dominantly produced a CD spectrum that corresponded to the extensive stacking, except at the lowest R ratio that was used in this work (R = 0.04). However, for cis-bis(N-methylpyridinium-4-yl)porphyrin (cis-BMPyP), the intensity of the apparent bisignate CD signal was too small to assign it to the extensive stacking. Moreover, the shape of the CD spectrum in the DNA absorption region showed that the conformation of poly[d(A-T)(2)] was retained, in contrast to the extensively stacked TMPyP and trans-BMPyP. In the extensively stacked TMPyP- poly[d(A-T)(2)] assembly, the large negative LD signal in the Soret band was observed suggesting that the direction of the molecular planes of TMPyP was close to perpendicular with respect to the orientation axis (flow axis). In contrast, the LD spectrum of the trans-BMPyP-poly[d(A-T)(2)] complex produced positive LD signal in the same wavelength region, suggesting the orientation of the molecular plane was nearly parallel relative to the flow direction. Surprisingly, the LD signal in the DNA absorption region for both of the porphyrins was positive. Therefore, the helix axis of the DNA was near perpendicular relative to the flow direction in the porphyrin-polynucleotide assembly.
URI
http://hdl.handle.net/YU.REPOSITORY/22361http://dx.doi.org/10.1021/jp1009687
ISSN
1520-6106
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이과대학 > 화학생화학부 > Articles
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