K. Kawai et al. / Tetrahedron Letters 43 (2002) 8083–8085
Table 2. Observed rate constant of the hole transfer (kobs
8085
)
1999, 6, 85.
+
from Py to oxG for Py and oxG containing ODNsa
4. Porath, D.; Bezryadin, A.; de Vries, S.; Dekker, C.
Nature 2000, 403, 635.
5. Nakatani, K.; Dohno, C.; Saito, I. J. Am. Chem. Soc.
2000, 122, 5893.
6. Nakatani, K.; Dohno, C.; Saito, I. J. Am. Chem. Soc.
1999, 121, 10854.
7. Meggers, E.; Michel-Beyerle, M. E.; Giese, B. J. Am.
Chem. Soc. 1998, 120, 12950.
ODN
Sequence
kobs (104 s−1
)
PyODN-mC
PyODN-C
PyODN-brC
5%-Py-AAmCACACACAAAA 13
3%-TToxGTGTGTGTTTT
5%-Py-AACACACACAAAA
3%-TToxGTGTGTGTTTT
5%-Py-AAbrCACACACAAAA
3%-TToxGTGTGTGTTTT
11
9.7
8. Sugiyama, H.; Saito, I. J. Am. Chem. Soc. 1996, 118,
7063.
a Pulse radiolysis was carried out in an Ar-saturated aqueous solution
containing 10 mM K2S2O8, 100 mM t-BuOH, 50 mM pH 7.0 Na
phosphate buffer, and 0.2 mM (strand conc.) ODN.
9. Saito, I.; Takayama, M.; Sugiyama, H.; Nakatani, K.;
Tsuchida, A.; Yamamoto, M. J. Am. Chem. Soc. 1995,
117, 6406.
10. Kawai, K.; Wata, Y.; Hara, M.; Tojo, S.; Majima, T. J.
Am. Chem. Soc. 2002, 124, 3586.
11. Kawai, K.; Wata, Y.; Ichinose, N.; Majima, T. Angew.
Chem., Int. Ed. 2000, 39, 4327.
12. Rogers, J. E.; Abraham, B.; Rostkowski, A.; Kelly, L. A.
Photochem. Photobiol. 2001, 74, 521.
13. Rogers, J. E.; Weiss, S. J.; Kelly, L. A. J. Am. Chem. Soc.
2000, 122, 427.
14. Rogers, J. E.; Kelly, L. A. J. Am. Chem. Soc. 1999, 121,
3854.
Scheme 3. Schematic representation of hole transfer, site
selective oxidation, and strand scission.
15. When enzymatic digestion was performed at 4°C, 2-
aminoimidazolone was identified as a guanine oxidation
product. See: Kino, K.; Saito, I.; Sugiyama, H. J. Am.
Chem. Soc. 1998, 120, 7373.
16. Kawai, K.; Takada, T.; Tojo, S.; Ichinose, N.; Majima,
T. J. Am. Chem. Soc. 2001, 123, 12688.
tively. Our results suggest that the direction of the hole
transfer and ultimate oxidation site in DNA may be
controlled by introducing a substituent on cytosine.
17. Kawai, K.; Takada, T.; Tojo, S.; Majima, T. Tetrahedron
Lett. 2002, 43, 89.
Acknowledgements
18. For comparison, differences between the oxidation poten-
tials of G in the G and GG sequences is about 0.05 V.
See: Lewis, F. D.; Liu, X. Y.; Liu, J. Q.; Hayes, R. T.;
Wasielewski, M. R. J. Am. Chem. Soc. 2000, 122, 12037.
19. Not only the hole transfer rate but also the hole trapping
rate determines the oxidation site of DNA. Nakatani, K.;
Dohno, C.; Saito, I. J. Am. Chem. Soc. 2001, 123, 9681
(however, there is no direct measurement of the hole
trapping rate of G or G in the GG, and GGG sequences
in DNA).
We thank the members of the Radiation Laboratory of
SANKEN, Osaka University for running the linear
accelerator. This work has been partly supported by a
Grant-in-Aid for Scientific Research from Ministry of
Education, Science, Sport and Culture of Japan.
References
20. Regulation of the hole transfer rate by hydrogen bonding
to protein was recently reported. See: Nakatani, K.;
Dohno, C.; Ogawa, A.; Saito, I. Chem. Biol. 2002, 9, 361.
1. Giese, B. Acc. Chem. Res. 2000, 33, 631.
2. Schuster, G. B. Acc. Chem. Res. 2000, 33, 253.
3. Nunez, M. E.; Hall, D. B.; Barton, J. K. Chem. Biol.