Electrochemical and capillary zone electrophoresis study of pyrimidine residues modification by osmium tetroxide, 2,2´-bipyridine. Detection of unpaired and mispaired thymines in DNA heteroduplexes.
|Year of publication||2009|
|Type||Article in Proceedings|
|Conference||XXIX. moderní elektrochemické metody - sborník příspěvků|
|MU Faculty or unit|
|Keywords||DNA; OsO4 bipy; voltammetry; capillary electrophoresis|
|Description||In this work we used capillary zone electrophoresis (CZE) in combination with square wave voltammetry (SWV) at a pyrolytic graphite electrode (PGE) to study reactivity of different pyrimidine residues, thymine (T), uracil (U), cytosine (C) and 5 methyl cytosine (meC), within a pentanucleotide AAAAY (where Y stands for the pyrimidine residue), towards Os,bipy. Since adenine practically does not react with Os,L, Y residues represent the only reactive centre within the pentamers and their reactivity can thus be easily compared. Both techniques revealed the order of the Y reactivities as follows: T>>MeC~U>C. Hence, our results confirmed (a) highly preferential modification of T among all Ys and (b) increased reactivity of MeC, compared to C that was reported by other authors. However, despite recent papers presenting Os,L modification as useful tool for MeC detection in DNA, the strong modification of T within natural DNA (where T is much more abundant than MeC) makes this approach hardly applicable for real analyses of DNA methylation.|