Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5372233 | Biophysical Chemistry | 2007 | 7 Pages |
Abstract
Whereas the emission from the ruthenium complex ÎÎ-[μ-bidppz(phen)4Ru2]4+ (P) is five times larger when intercalated into poly(dAdT)2 than when intercalated into ct-DNA, the homologue ÎÎ-[μ-bidppz(bipy)4Ru2]4+ (B) has a smaller quantum yield and a red-shifted emission. The origin of this difference is here investigated by studying intercalation into oligonucleotides containing a central AT-tract. Increasing the length of the AT-tract increases the emission quantum yield for P but decreases it for B. However, not even four helix turns of AT base pairs is enough to mimic poly(dAdT)2. B and P thus use the increased flexibility with increasing length of the AT-tract in opposite ways, whereas B gets more prone to quenching by water, P gets more protected from quenching. The earlier reported gradual increase of the intercalation rate with AT-stretch length is thus paralleled by a gradual change in the equilibrium properties of the intercalated state.
Keywords
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Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Fredrik Westerlund, Per Lincoln,