CHED 220 |
| Cation-pi interactions occur when a bound ion interacts with the aromatic face of a DNA base. Many high resolution DNA structures have been deposited in the Nucleic Acid Database (NDB) since the initial publication describing DNA cation-pi interactions. A survey of the NDB produced 8 structures with resolution 1.6 Ǻ or higher that contain groove-bound cations but no significant chemical modifications or bound ligands. Using Visual Basic for Application programs to calculate the distances and angles between base centroids and bound cations, cations at distances less than 5.5 Ǻ and angles less than 55 degrees from a base centroid were isolated as cation-pi interactions. Seven of the eight structures analyzed contained cation-pi interactions, which were found to occur in the major and minor grooves, sequence specifically, with all four DNA bases, and to induce DNA base unstacking. We conclude cation-pi interactions are common and that they induce DNA distortion.
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Undergraduate Research Poster Session: Biochemistry
2:30 PM-4:30 PM, Monday, 11 September 2006 Moscone Center -- Hall D, Poster
Division of Chemical Education |