Polynucleotides and Single-Stranded DNA Fragments - Free-Radical-Induced DNA Damage and Its Repair - page 326

Table 11.1. Rate of oxidation of some oligonucleotides by CO 3 • - and SO 4 • - . (Joffe et al.
2003b; Shafirovich et al. 2004)

k/dm 3 mol -1 s -1 Radical Oligonucleotide

CO 3 • - 2.4 ( ± 0.3) × 10 7

5 ′ -dCCATC G CTACC

CO 3 • - 3.2 ( ± 0.4) × 10 8 5 ′ -dCCATC[ 8-oxo-G ]CTACC

CO 3 • - 1.4 ( ± 0.2) × 10 6a

Duplex d(TATAAC G TTATA)

CO 3 • - 1.9 ( ± 0.2) × 10 7

Duplex d(AACGCGAAT TCGCGT T)

CO 3 • - 5.8 ( ± 0.6) × 10 7 5 ′ -dCCATC[ Sp ]CTACC

SO 4 • - 3.2 ( ± 0.3) × 10 9

5 ′ -dCCATCGCTACC

a At 15 °C

subsequently deaminates, the • OH-adduct product (on the left) must have lost
water in an otherwise not yet observed 're-aromatization' reaction.
The same type of reaction is given by the • OH-adduct at C (6) of the T moi-

ety.

The reaction not only proceeds in the 5 direction but also in the reverse di-

rection as shown by the products depicted above.
ODNs have also been used for the study of the reactive intermediates that
play a role in peroxynitrite reactions such as CO 3 • − and • NO 2 (Chap. 2.4). The
CO 3 • − radical reacts quite fast with G-containing ODNs (Table 11.1).
In these ODNs, G is oxidized to 8-oxo-G. This product is much more easily
oxidized by CO 3 • − and gives rise to the Sp lesion which is also readily oxidized
(for mechanistic details see Chap. 10.14).

′→ 3 ′