CHED 810 |
| Oxidative damage to DNA can cause disease and one form of oxidative damage is the DNA-protein crosslink. Guanine (G) is easily oxidized, and proton transfer from the guanine radical cation to cytosine is favorable. We are studying how the G radical protonation state influences the DNA-protein crosslinking reaction with histone. In DNA 20-mer duplexes, methyl or bromo was substituted at the C5 position to alter the cytosine basicity. Crosslinking was then induced by the flash-quench technique and gel shift and the chloroform extraction assays revealed that the crosslinking was most efficient with the 5'-bromocytosine DNA. This was expected because the cation radical is more reactive and the more weakly basic 5-bromocytosine should allow the guanine cation radical to persist longer. Preliminary results indicate that this trend holds at pH 4.5 as well as pH 7 but that the crosslink appears more labile at acidic pH. |
|
Undergraduate Research Poster Session: Biochemistry
2:00 PM-4:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Poster
Division of Chemical Education |