|
Back to Colloquia
Physics Colloquium Friday, Oct. 20th, 2006,
4:00 P.M.
E300 Math/Science
Center; Refreshments at 3:30 P.M. in
Room E200
Angelo Bongiorno
Georgia Institute of Technology
Oxidative damage to DNA: role of sequence and strand direction
We use quantum mechanics/molecular mechanics (QM/MM)
calculations
to address the oxidative DNA damage process resulting from
water
addition to guanine (G) radical cations. In particular, we
consider
DNA duplexes containing GG steps embedded in AGGA or TGGT
sequences
(A,T for adenine and thymine, respectively) and we focus on
the
direction- and sequence-sensitivity of the oxidation process
at the GG
doublets.
In accord with gel electrophoresis and auto-radiography
experiments,
our calculations show that the oxidation process occurs
predominantly
at the 5'-G of GG doublets, and that it is markedly
sequence-sensitive.
Our study suggests that the rate of water addition at guanine
radical
cations is governed mainly by steric effects.
|
|