| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 5371461 | Biophysical Chemistry | 2011 | 8 Pages |
The B form of DNA exists in equilibrium with the Z form and is mainly affected by sequence, electrostatic interactions, and steric effects. C8-purine substitution shifts the equilibrium toward the Z form though how this interaction overcomes the unfavorable electrostatic interactions and decrease in stacking in the Z form has not been determined. Here, a series of C8-arylguanine derivatives, bearing a para-substituent were prepared and the B/Z equilibrium determined. B/Z ratios were measured by CD and conformational effects of the aryl substitution determined by NMR spectroscopy and molecular modeling. The para-substituent was found to have a significant effect on the B/Z DNA equilibrium caused by altering base-pair stacking of the B form and modifying the hydration/ion shell of the B form. A unique melting temperature versus salt concentration was observed and provides evidence relevant to the mechanism of B/Z conformational interconversion.
Graphical AbstractDownload full-size imageResearch HighlightsâºC8-guanine arylation causes B/Z DNA equilibrium to shift to Z form. âºPosition of equilibrium strongly depends on the aryl para-substituent. âºArylation disrupts hydration shell and destabilizes the B form. âºNovel salt concentration dependence of melting temperature.
