Kawai Kiyohiko, Osakada Yasuko, Takada Tadao, Fujitsuka Mamoru, Majima Tetsuro
Contribution from The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan.
J Am Chem Soc. 2004 Oct 13;126(40):12843-6. doi: 10.1021/ja0475813.
A series of naphthalimide (NI)- and 5-bromocytosine ((br)C)-modified oligodeoxynucleotides (ODNs) were prepared, and their lifetimes of the charge-separated states during the photosensitized one-electron oxidation of DNA were measured. Various lifetimes of the charge-separated states were observed depending on the sequence and the incorporation sites of (br)C, and the oxidation potential of G in the (br)C:G base-pair relative to that of G in the C:G base-pair and in the GGG sequence was determined by comparing the lifetimes of the charge-separated states. The change in the cytosine C5 hydrogen to bromine resulted in a 24 mV increase in the oxidation potential of G in the (br)C:G base-pair as compared to that of G in the C:G base-pair, the value of which is comparable to a 58 mV decrease in the oxidation potential of G in the GGG sequence. These results clearly demonstrate that hole transfer in DNA can be controlled through hydrogen bonding by introducing a substituent on the cytosine.
制备了一系列萘二甲酰亚胺（NI）和5-溴胞嘧啶（（br）C）修饰的寡脱氧核苷酸（ODN），并测量了它们在DNA光敏单电子氧化过程中电荷分离态的寿命。根据（br）C的序列和掺入位点，观察到了电荷分离态的不同寿命，并通过比较电荷分离态的寿命，确定了（br）C：G碱基对中G相对于C：G碱基对和GGG序列中G的氧化电位。胞嘧啶C5位的氢被溴取代后，（br）C：G碱基对中G的氧化电位比C：G碱基对中G的氧化电位增加了24 mV，该值与GGG序列中G的氧化电位降低58 mV相当。这些结果清楚地表明，通过在胞嘧啶上引入取代基，可以通过氢键控制DNA中的空穴转移。
