Lifetime regulation of the charge-separated state in DNA by modulating the oxidation potential of guanine in DNA through hydrogen bonding.
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.
Contribution from The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan. kiyohiko@sanken.osaka-u.ac.jp
Kiyohiko
K
Kawai
Yasuko
Y
Osakada
Tadao
T
Takada
Mamoru
M
Fujitsuka
Tetsuro
T
Majima
D015057:1-Naphthylamine / Q000737:chemistry; D003596:Cytosine / Q000031:analogs & derivatives* / Q000737:chemistry; D004247:DNA / Q000737:chemistry*; D006147:Guanine / Q000737:chemistry*; D006860:Hydrogen Bonding; D007700:Kinetics; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry*; D010084:Oxidation-Reduction; D010777:Photochemistry; D010782:Photolysis
D009841:Oligonucleotides; C103182:5-bromocytosine; D006147:Guanine; D003596:Cytosine; D004247:DNA; D015057:1-Naphthylamine